/* binder.c
 *
 * Android IPC Subsystem
 *
 * Copyright (C) 2007-2008 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <asm/cacheflush.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/fdtable.h>
#include <linux/file.h>
#include <linux/freezer.h>
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/nsproxy.h>
#include <linux/poll.h>
#include <linux/debugfs.h>
#include <linux/rbtree.h>
#include <linux/version.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#else
#include <linux/signal.h>
#include <linux/mm.h>
#endif
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/pid_namespace.h>
#include <linux/security.h>

#ifdef CONFIG_ANDROID_BINDER_IPC_32BIT
#define BINDER_IPC_32BIT 1
#endif

/* Until I upstream a better version of this patch choose an arbitrary major
 * number in the high end spectrum that has not yet been given away and is
 * unlikely to be given away in the near future.
 */
#define BINDER_DKMS_MAJOR 511
#define BINDER_DKMS_MAX_MINOR 1024

#include "binder.h"
#include "binder_trace.h"

#ifndef MAX_NICE
#define MAX_NICE 19
#endif

static DEFINE_MUTEX(binder_main_lock);
static DEFINE_MUTEX(binder_deferred_lock);
static DEFINE_MUTEX(binder_mmap_lock);
static DEFINE_MUTEX(binder_devices_mtx);

static HLIST_HEAD(binder_devices);
static HLIST_HEAD(binder_procs);
static HLIST_HEAD(binder_deferred_list);
static HLIST_HEAD(binder_dead_nodes);

static struct dentry *binder_debugfs_dir_entry_root;
static struct dentry *binder_debugfs_dir_entry_proc;
static int binder_last_id;

#define BINDER_DEBUG_ENTRY(name) \
static int binder_##name##_open(struct inode *inode, struct file *file) \
{ \
    return single_open(file, binder_##name##_show, inode->i_private); \
} \
\
static const struct file_operations binder_##name##_fops = { \
    .owner = THIS_MODULE, \
    .open = binder_##name##_open, \
    .read = seq_read, \
    .llseek = seq_lseek, \
    .release = single_release, \
}

static int binder_proc_show(struct seq_file *m, void *unused);
BINDER_DEBUG_ENTRY(proc);

/* This is only defined in include/asm-arm/sizes.h */
#ifndef SZ_1K
#define SZ_1K                               0x400
#endif

#ifndef SZ_4M
#define SZ_4M                               0x400000
#endif

#define FORBIDDEN_MMAP_FLAGS                (VM_WRITE)

#define BINDER_SMALL_BUF_SIZE (PAGE_SIZE * 64)

enum {
    BINDER_DEBUG_USER_ERROR             = 1U << 0,
    BINDER_DEBUG_FAILED_TRANSACTION     = 1U << 1,
    BINDER_DEBUG_DEAD_TRANSACTION       = 1U << 2,
    BINDER_DEBUG_OPEN_CLOSE             = 1U << 3,
    BINDER_DEBUG_DEAD_BINDER            = 1U << 4,
    BINDER_DEBUG_DEATH_NOTIFICATION     = 1U << 5,
    BINDER_DEBUG_READ_WRITE             = 1U << 6,
    BINDER_DEBUG_USER_REFS              = 1U << 7,
    BINDER_DEBUG_THREADS                = 1U << 8,
    BINDER_DEBUG_TRANSACTION            = 1U << 9,
    BINDER_DEBUG_TRANSACTION_COMPLETE   = 1U << 10,
    BINDER_DEBUG_FREE_BUFFER            = 1U << 11,
    BINDER_DEBUG_INTERNAL_REFS          = 1U << 12,
    BINDER_DEBUG_BUFFER_ALLOC           = 1U << 13,
    BINDER_DEBUG_PRIORITY_CAP           = 1U << 14,
    BINDER_DEBUG_BUFFER_ALLOC_ASYNC     = 1U << 15,
};
static uint32_t binder_debug_mask = BINDER_DEBUG_USER_ERROR |
    BINDER_DEBUG_FAILED_TRANSACTION | BINDER_DEBUG_DEAD_TRANSACTION;

module_param_named(debug_mask, binder_debug_mask, uint, S_IWUSR | S_IRUGO);

static bool binder_debug_no_lock;
module_param_named(proc_no_lock, binder_debug_no_lock, bool, S_IWUSR | S_IRUGO);

static int binder_devices_param = 1;
module_param_named(num_devices, binder_devices_param, int, 0444);

static DECLARE_WAIT_QUEUE_HEAD(binder_user_error_wait);
static int binder_stop_on_user_error;

static int binder_set_stop_on_user_error(const char *val,
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
                     const struct kernel_param *kp)
#else
                     struct kernel_param *kp)
#endif
{
    int ret;

    ret = param_set_int(val, kp);
    if (binder_stop_on_user_error < 2)
        wake_up(&binder_user_error_wait);
    return ret;
}
module_param_call(stop_on_user_error, binder_set_stop_on_user_error,
    param_get_int, &binder_stop_on_user_error, S_IWUSR | S_IRUGO);

#define binder_debug(mask, x...) \
    do { \
        if (binder_debug_mask & mask) \
            pr_info(x); \
    } while (0)

#define binder_user_error(x...) \
    do { \
        if (binder_debug_mask & BINDER_DEBUG_USER_ERROR) \
            pr_info(x); \
        if (binder_stop_on_user_error) \
            binder_stop_on_user_error = 2; \
    } while (0)

#define to_flat_binder_object(hdr) \
    container_of(hdr, struct flat_binder_object, hdr)

#define to_binder_fd_object(hdr) container_of(hdr, struct binder_fd_object, hdr)

#define to_binder_buffer_object(hdr) \
    container_of(hdr, struct binder_buffer_object, hdr)

#define to_binder_fd_array_object(hdr) \
    container_of(hdr, struct binder_fd_array_object, hdr)

enum binder_stat_types {
    BINDER_STAT_PROC,
    BINDER_STAT_THREAD,
    BINDER_STAT_NODE,
    BINDER_STAT_REF,
    BINDER_STAT_DEATH,
    BINDER_STAT_TRANSACTION,
    BINDER_STAT_TRANSACTION_COMPLETE,
    BINDER_STAT_COUNT
};

struct binder_stats {
    int br[_IOC_NR(BR_FAILED_REPLY) + 1];
    int bc[_IOC_NR(BC_REPLY_SG) + 1];
    int obj_created[BINDER_STAT_COUNT];
    int obj_deleted[BINDER_STAT_COUNT];
};

static struct binder_stats binder_stats;

static inline void binder_stats_deleted(enum binder_stat_types type)
{
    binder_stats.obj_deleted[type]++;
}

static inline void binder_stats_created(enum binder_stat_types type)
{
    binder_stats.obj_created[type]++;
}

struct binder_transaction_log_entry {
    int debug_id;
    int call_type;
    int from_proc;
    int from_thread;
    int target_handle;
    int to_proc;
    int to_thread;
    int to_node;
    int data_size;
    int offsets_size;
    const char *context_name;
};
struct binder_transaction_log {
    int next;
    int full;
    struct binder_transaction_log_entry entry[32];
};
static struct binder_transaction_log binder_transaction_log;
static struct binder_transaction_log binder_transaction_log_failed;

static struct binder_transaction_log_entry *binder_transaction_log_add(
    struct binder_transaction_log *log)
{
    struct binder_transaction_log_entry *e;

    e = &log->entry[log->next];
    memset(e, 0, sizeof(*e));
    log->next++;
    if (log->next == ARRAY_SIZE(log->entry)) {
        log->next = 0;
        log->full = 1;
    }
    return e;
}

struct binder_context {
    struct binder_node *binder_context_mgr_node;
    kuid_t binder_context_mgr_uid;
    const char *name;
};

struct binder_device {
    struct hlist_node hlist;
    struct cdev cdev;
    struct device class_dev;
    struct binder_context context;
};

struct binder_work {
    struct list_head entry;
    enum {
        BINDER_WORK_TRANSACTION = 1,
        BINDER_WORK_TRANSACTION_COMPLETE,
        BINDER_WORK_NODE,
        BINDER_WORK_DEAD_BINDER,
        BINDER_WORK_DEAD_BINDER_AND_CLEAR,
        BINDER_WORK_CLEAR_DEATH_NOTIFICATION,
    } type;
};

struct binder_node {
    int debug_id;
    struct binder_work work;
    union {
        struct rb_node rb_node;
        struct hlist_node dead_node;
    };
    struct binder_proc *proc;
    struct hlist_head refs;
    int internal_strong_refs;
    int local_weak_refs;
    int local_strong_refs;
    binder_uintptr_t ptr;
    binder_uintptr_t cookie;
    unsigned has_strong_ref:1;
    unsigned pending_strong_ref:1;
    unsigned has_weak_ref:1;
    unsigned pending_weak_ref:1;
    unsigned has_async_transaction:1;
    unsigned accept_fds:1;
    unsigned min_priority:8;
    struct list_head async_todo;
};

struct binder_ref_death {
    struct binder_work work;
    binder_uintptr_t cookie;
};

struct binder_ref {
    /* Lookups needed: */
    /*   node + proc => ref (transaction) */
    /*   desc + proc => ref (transaction, inc/dec ref) */
    /*   node => refs + procs (proc exit) */
    int debug_id;
    struct rb_node rb_node_desc;
    struct rb_node rb_node_node;
    struct hlist_node node_entry;
    struct binder_proc *proc;
    struct binder_node *node;
    uint32_t desc;
    int strong;
    int weak;
    struct binder_ref_death *death;
};

struct binder_buffer {
    struct list_head entry; /* free and allocated entries by address */
    struct rb_node rb_node; /* free entry by size or allocated entry */
                /* by address */
    unsigned free:1;
    unsigned allow_user_free:1;
    unsigned async_transaction:1;
    unsigned debug_id:29;

    struct binder_transaction *transaction;

    struct binder_node *target_node;
    size_t data_size;
    size_t offsets_size;
    size_t extra_buffers_size;
    uint8_t data[0];
};

enum binder_deferred_state {
    BINDER_DEFERRED_PUT_FILES    = 0x01,
    BINDER_DEFERRED_FLUSH        = 0x02,
    BINDER_DEFERRED_RELEASE      = 0x04,
};

struct binder_proc {
    struct hlist_node proc_node;
    struct rb_root threads;
    struct rb_root nodes;
    struct rb_root refs_by_desc;
    struct rb_root refs_by_node;
    int pid;
    struct vm_area_struct *vma;
    struct mm_struct *vma_vm_mm;
    struct task_struct *tsk;
    struct files_struct *files;
    struct hlist_node deferred_work_node;
    int deferred_work;
    void *buffer;
    ptrdiff_t user_buffer_offset;

    struct list_head buffers;
    struct rb_root free_buffers;
    struct rb_root allocated_buffers;
    size_t free_async_space;

    struct page **pages;
    size_t buffer_size;
    uint32_t buffer_free;
    struct list_head todo;
    wait_queue_head_t wait;
    struct binder_stats stats;
    struct list_head delivered_death;
    int max_threads;
    int requested_threads;
    int requested_threads_started;
    int ready_threads;
    long default_priority;
    struct dentry *debugfs_entry;
    struct binder_context *context;
};

enum {
    BINDER_LOOPER_STATE_REGISTERED  = 0x01,
    BINDER_LOOPER_STATE_ENTERED     = 0x02,
    BINDER_LOOPER_STATE_EXITED      = 0x04,
    BINDER_LOOPER_STATE_INVALID     = 0x08,
    BINDER_LOOPER_STATE_WAITING     = 0x10,
    BINDER_LOOPER_STATE_NEED_RETURN = 0x20
};

struct binder_thread {
    struct binder_proc *proc;
    struct rb_node rb_node;
    int pid;
    int looper;
    struct binder_transaction *transaction_stack;
    struct list_head todo;
    uint32_t return_error; /* Write failed, return error code in read buf */
    uint32_t return_error2; /* Write failed, return error code in read */
        /* buffer. Used when sending a reply to a dead process that */
        /* we are also waiting on */
    wait_queue_head_t wait;
    struct binder_stats stats;
};

struct binder_transaction {
    int debug_id;
    struct binder_work work;
    struct binder_thread *from;
    struct binder_transaction *from_parent;
    struct binder_proc *to_proc;
    struct binder_thread *to_thread;
    struct binder_transaction *to_parent;
    unsigned need_reply:1;
    /* unsigned is_dead:1; */   /* not used at the moment */

    struct binder_buffer *buffer;
    unsigned int    code;
    unsigned int    flags;
    long    priority;
    long    saved_priority;
    kuid_t  sender_euid;
};

static void
binder_defer_work(struct binder_proc *proc, enum binder_deferred_state defer);

static int task_get_unused_fd_flags(struct binder_proc *proc, int flags)
{
    struct files_struct *files = proc->files;
    unsigned long rlim_cur;
    unsigned long irqs;

    if (files == NULL)
        return -ESRCH;

    if (!lock_task_sighand(proc->tsk, &irqs))
        return -EMFILE;

    rlim_cur = task_rlimit(proc->tsk, RLIMIT_NOFILE);
    unlock_task_sighand(proc->tsk, &irqs);

    return __alloc_fd(files, 0, rlim_cur, flags);
}

/*
 * copied from fd_install
 */
static void task_fd_install(
    struct binder_proc *proc, unsigned int fd, struct file *file)
{
    if (proc->files)
        __fd_install(proc->files, fd, file);
}

/*
 * copied from sys_close
 */
static long task_close_fd(struct binder_proc *proc, unsigned int fd)
{
    int retval;

    if (proc->files == NULL)
        return -ESRCH;

    retval = __close_fd(proc->files, fd);
    /* can't restart close syscall because file table entry was cleared */
    if (unlikely(retval == -ERESTARTSYS ||
             retval == -ERESTARTNOINTR ||
             retval == -ERESTARTNOHAND ||
             retval == -ERESTART_RESTARTBLOCK))
        retval = -EINTR;

    return retval;
}

static inline void binder_lock(const char *tag)
{
    trace_binder_lock(tag);
    mutex_lock(&binder_main_lock);
    trace_binder_locked(tag);
}

static inline void binder_unlock(const char *tag)
{
    trace_binder_unlock(tag);
    mutex_unlock(&binder_main_lock);
}

#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 16, 0)
/*
 * Convert rlimit style value [1,40] to nice value [-20, 19].
 */
static inline long rlimit_to_nice(long prio)
{
    return (MAX_NICE - prio + 1);
}
#endif

static void binder_set_nice(long nice)
{
    long min_nice;

    if (can_nice(current, nice)) {
        set_user_nice(current, nice);
        return;
    }
    min_nice = rlimit_to_nice(current->signal->rlim[RLIMIT_NICE].rlim_cur);
    binder_debug(BINDER_DEBUG_PRIORITY_CAP,
             "%d: nice value %ld not allowed use %ld instead\n",
              current->pid, nice, min_nice);
    set_user_nice(current, min_nice);
    if (min_nice <= MAX_NICE)
        return;
}

static size_t binder_buffer_size(struct binder_proc *proc,
                 struct binder_buffer *buffer)
{
    if (list_is_last(&buffer->entry, &proc->buffers))
        return proc->buffer + proc->buffer_size - (void *)buffer->data;
    return (size_t)list_entry(buffer->entry.next,
              struct binder_buffer, entry) - (size_t)buffer->data;
}

static void binder_insert_free_buffer(struct binder_proc *proc,
                      struct binder_buffer *new_buffer)
{
    struct rb_node **p = &proc->free_buffers.rb_node;
    struct rb_node *parent = NULL;
    struct binder_buffer *buffer;
    size_t buffer_size;
    size_t new_buffer_size;

    BUG_ON(!new_buffer->free);

    new_buffer_size = binder_buffer_size(proc, new_buffer);

    binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
             "%d: add free buffer, size %zd, at %p\n",
              proc->pid, new_buffer_size, new_buffer);

    while (*p) {
        parent = *p;
        buffer = rb_entry(parent, struct binder_buffer, rb_node);
        BUG_ON(!buffer->free);

        buffer_size = binder_buffer_size(proc, buffer);

        if (new_buffer_size < buffer_size)
            p = &parent->rb_left;
        else
            p = &parent->rb_right;
    }
    rb_link_node(&new_buffer->rb_node, parent, p);
    rb_insert_color(&new_buffer->rb_node, &proc->free_buffers);
}

static void binder_insert_allocated_buffer(struct binder_proc *proc,
                       struct binder_buffer *new_buffer)
{
    struct rb_node **p = &proc->allocated_buffers.rb_node;
    struct rb_node *parent = NULL;
    struct binder_buffer *buffer;

    BUG_ON(new_buffer->free);

    while (*p) {
        parent = *p;
        buffer = rb_entry(parent, struct binder_buffer, rb_node);
        BUG_ON(buffer->free);

        if (new_buffer < buffer)
            p = &parent->rb_left;
        else if (new_buffer > buffer)
            p = &parent->rb_right;
        else
            BUG();
    }
    rb_link_node(&new_buffer->rb_node, parent, p);
    rb_insert_color(&new_buffer->rb_node, &proc->allocated_buffers);
}

static struct binder_buffer *binder_buffer_lookup(struct binder_proc *proc,
                          uintptr_t user_ptr)
{
    struct rb_node *n = proc->allocated_buffers.rb_node;
    struct binder_buffer *buffer;
    struct binder_buffer *kern_ptr;

    kern_ptr = (struct binder_buffer *)(user_ptr - proc->user_buffer_offset
        - offsetof(struct binder_buffer, data));

    while (n) {
        buffer = rb_entry(n, struct binder_buffer, rb_node);
        BUG_ON(buffer->free);

        if (kern_ptr < buffer)
            n = n->rb_left;
        else if (kern_ptr > buffer)
            n = n->rb_right;
        else
            return buffer;
    }
    return NULL;
}

static int binder_update_page_range(struct binder_proc *proc, int allocate,
                    void *start, void *end,
                    struct vm_area_struct *vma)
{
    void *page_addr;
    unsigned long user_page_addr;
    struct page **page;
    struct mm_struct *mm;

    binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
             "%d: %s pages %p-%p\n", proc->pid,
             allocate ? "allocate" : "free", start, end);

    if (end <= start)
        return 0;

    trace_binder_update_page_range(proc, allocate, start, end);

    if (vma)
        mm = NULL;
    else
        mm = get_task_mm(proc->tsk);

    if (mm) {
        down_write(&mm->mmap_sem);
        vma = proc->vma;
        if (vma && mm != proc->vma_vm_mm) {
            pr_err("%d: vma mm and task mm mismatch\n",
                proc->pid);
            vma = NULL;
        }
    }

    if (allocate == 0)
        goto free_range;

    if (vma == NULL) {
        pr_err("%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
            proc->pid);
        goto err_no_vma;
    }

    for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
        int ret;

        page = &proc->pages[(page_addr - proc->buffer) / PAGE_SIZE];

        BUG_ON(*page);
        *page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
        if (*page == NULL) {
            pr_err("%d: binder_alloc_buf failed for page at %p\n",
                proc->pid, page_addr);
            goto err_alloc_page_failed;
        }
        ret = map_kernel_range_noflush((unsigned long)page_addr,
                    PAGE_SIZE, PAGE_KERNEL, page);
        flush_cache_vmap((unsigned long)page_addr,
                (unsigned long)page_addr + PAGE_SIZE);
        if (ret != 1) {
            pr_err("%d: binder_alloc_buf failed to map page at %p in kernel\n",
                   proc->pid, page_addr);
            goto err_map_kernel_failed;
        }
        user_page_addr =
            (uintptr_t)page_addr + proc->user_buffer_offset;
        ret = vm_insert_page(vma, user_page_addr, page[0]);
        if (ret) {
            pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
                   proc->pid, user_page_addr);
            goto err_vm_insert_page_failed;
        }
        /* vm_insert_page does not seem to increment the refcount */
    }
    if (mm) {
        up_write(&mm->mmap_sem);
        mmput(mm);
    }
    return 0;

free_range:
    for (page_addr = end - PAGE_SIZE; page_addr >= start;
         page_addr -= PAGE_SIZE) {
        page = &proc->pages[(page_addr - proc->buffer) / PAGE_SIZE];
        if (vma)
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
            zap_page_range(vma, (uintptr_t)page_addr +
                proc->user_buffer_offset, PAGE_SIZE);
#else
            zap_page_range(vma, (uintptr_t)page_addr +
                proc->user_buffer_offset, PAGE_SIZE, NULL);
#endif
err_vm_insert_page_failed:
        unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
err_map_kernel_failed:
        __free_page(*page);
        *page = NULL;
err_alloc_page_failed:
        ;
    }
err_no_vma:
    if (mm) {
        up_write(&mm->mmap_sem);
        mmput(mm);
    }
    return -ENOMEM;
}

static struct binder_buffer *binder_alloc_buf(struct binder_proc *proc,
                          size_t data_size,
                          size_t offsets_size,
                          size_t extra_buffers_size,
                          int is_async)
{
    struct rb_node *n = proc->free_buffers.rb_node;
    struct binder_buffer *buffer;
    size_t buffer_size;
    struct rb_node *best_fit = NULL;
    void *has_page_addr;
    void *end_page_addr;
    size_t size, data_offsets_size;

    if (proc->vma == NULL) {
        pr_err("%d: binder_alloc_buf, no vma\n",
               proc->pid);
        return NULL;
    }

    data_offsets_size = ALIGN(data_size, sizeof(void *)) +
        ALIGN(offsets_size, sizeof(void *));

    if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
        binder_user_error("%d: got transaction with invalid size %zd-%zd\n",
                proc->pid, data_size, offsets_size);
        return NULL;
    }
    size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
    if (size < data_offsets_size || size < extra_buffers_size) {
        binder_user_error("%d: got transaction with invalid extra_buffers_size %zd\n",
                  proc->pid, extra_buffers_size);
        return NULL;
    }
    if (is_async &&
        proc->free_async_space < size + sizeof(struct binder_buffer)) {
        binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                 "%d: binder_alloc_buf size %zd failed, no async space left\n",
                  proc->pid, size);
        return NULL;
    }

    while (n) {
        buffer = rb_entry(n, struct binder_buffer, rb_node);
        BUG_ON(!buffer->free);
        buffer_size = binder_buffer_size(proc, buffer);

        if (size < buffer_size) {
            best_fit = n;
            n = n->rb_left;
        } else if (size > buffer_size)
            n = n->rb_right;
        else {
            best_fit = n;
            break;
        }
    }
    if (best_fit == NULL) {
        pr_err("%d: binder_alloc_buf size %zd failed, no address space\n",
            proc->pid, size);
        return NULL;
    }
    if (n == NULL) {
        buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
        buffer_size = binder_buffer_size(proc, buffer);
    }

    binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
             "%d: binder_alloc_buf size %zd got buffer %p size %zd\n",
              proc->pid, size, buffer, buffer_size);

    has_page_addr =
        (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK);
    if (n == NULL) {
        if (size + sizeof(struct binder_buffer) + 4 >= buffer_size)
            buffer_size = size; /* no room for other buffers */
        else
            buffer_size = size + sizeof(struct binder_buffer);
    }
    end_page_addr =
        (void *)PAGE_ALIGN((uintptr_t)buffer->data + buffer_size);
    if (end_page_addr > has_page_addr)
        end_page_addr = has_page_addr;
    if (binder_update_page_range(proc, 1,
        (void *)PAGE_ALIGN((uintptr_t)buffer->data), end_page_addr, NULL))
        return NULL;

    rb_erase(best_fit, &proc->free_buffers);
    buffer->free = 0;
    binder_insert_allocated_buffer(proc, buffer);
    if (buffer_size != size) {
        struct binder_buffer *new_buffer = (void *)buffer->data + size;

        list_add(&new_buffer->entry, &buffer->entry);
        new_buffer->free = 1;
        binder_insert_free_buffer(proc, new_buffer);
    }
    binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
             "%d: binder_alloc_buf size %zd got %p\n",
              proc->pid, size, buffer);
    buffer->data_size = data_size;
    buffer->offsets_size = offsets_size;
    buffer->extra_buffers_size = extra_buffers_size;
    buffer->async_transaction = is_async;
    if (is_async) {
        proc->free_async_space -= size + sizeof(struct binder_buffer);
        binder_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
                 "%d: binder_alloc_buf size %zd async free %zd\n",
                  proc->pid, size, proc->free_async_space);
    }

    return buffer;
}

static void *buffer_start_page(struct binder_buffer *buffer)
{
    return (void *)((uintptr_t)buffer & PAGE_MASK);
}

static void *buffer_end_page(struct binder_buffer *buffer)
{
    return (void *)(((uintptr_t)(buffer + 1) - 1) & PAGE_MASK);
}

static void binder_delete_free_buffer(struct binder_proc *proc,
                      struct binder_buffer *buffer)
{
    struct binder_buffer *prev, *next = NULL;
    int free_page_end = 1;
    int free_page_start = 1;

    BUG_ON(proc->buffers.next == &buffer->entry);
    prev = list_entry(buffer->entry.prev, struct binder_buffer, entry);
    BUG_ON(!prev->free);
    if (buffer_end_page(prev) == buffer_start_page(buffer)) {
        free_page_start = 0;
        if (buffer_end_page(prev) == buffer_end_page(buffer))
            free_page_end = 0;
        binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                 "%d: merge free, buffer %p share page with %p\n",
                  proc->pid, buffer, prev);
    }

    if (!list_is_last(&buffer->entry, &proc->buffers)) {
        next = list_entry(buffer->entry.next,
                  struct binder_buffer, entry);
        if (buffer_start_page(next) == buffer_end_page(buffer)) {
            free_page_end = 0;
            if (buffer_start_page(next) ==
                buffer_start_page(buffer))
                free_page_start = 0;
            binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                     "%d: merge free, buffer %p share page with %p\n",
                      proc->pid, buffer, prev);
        }
    }
    list_del(&buffer->entry);
    if (free_page_start || free_page_end) {
        binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                 "%d: merge free, buffer %p do not share page%s%s with %p or %p\n",
                 proc->pid, buffer, free_page_start ? "" : " end",
                 free_page_end ? "" : " start", prev, next);
        binder_update_page_range(proc, 0, free_page_start ?
            buffer_start_page(buffer) : buffer_end_page(buffer),
            (free_page_end ? buffer_end_page(buffer) :
            buffer_start_page(buffer)) + PAGE_SIZE, NULL);
    }
}

static void binder_free_buf(struct binder_proc *proc,
                struct binder_buffer *buffer)
{
    size_t size, buffer_size;

    buffer_size = binder_buffer_size(proc, buffer);

    size = ALIGN(buffer->data_size, sizeof(void *)) +
        ALIGN(buffer->offsets_size, sizeof(void *)) +
        ALIGN(buffer->extra_buffers_size, sizeof(void *));

    binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
             "%d: binder_free_buf %p size %zd buffer_size %zd\n",
              proc->pid, buffer, size, buffer_size);

    BUG_ON(buffer->free);
    BUG_ON(size > buffer_size);
    BUG_ON(buffer->transaction != NULL);
    BUG_ON((void *)buffer < proc->buffer);
    BUG_ON((void *)buffer > proc->buffer + proc->buffer_size);

    if (buffer->async_transaction) {
        proc->free_async_space += size + sizeof(struct binder_buffer);

        binder_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
                 "%d: binder_free_buf size %zd async free %zd\n",
                  proc->pid, size, proc->free_async_space);
    }

    binder_update_page_range(proc, 0,
        (void *)PAGE_ALIGN((uintptr_t)buffer->data),
        (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK),
        NULL);
    rb_erase(&buffer->rb_node, &proc->allocated_buffers);
    buffer->free = 1;
    if (!list_is_last(&buffer->entry, &proc->buffers)) {
        struct binder_buffer *next = list_entry(buffer->entry.next,
                        struct binder_buffer, entry);

        if (next->free) {
            rb_erase(&next->rb_node, &proc->free_buffers);
            binder_delete_free_buffer(proc, next);
        }
    }
    if (proc->buffers.next != &buffer->entry) {
        struct binder_buffer *prev = list_entry(buffer->entry.prev,
                        struct binder_buffer, entry);

        if (prev->free) {
            binder_delete_free_buffer(proc, buffer);
            rb_erase(&prev->rb_node, &proc->free_buffers);
            buffer = prev;
        }
    }
    binder_insert_free_buffer(proc, buffer);
}

static struct binder_node *binder_get_node(struct binder_proc *proc,
                       binder_uintptr_t ptr)
{
    struct rb_node *n = proc->nodes.rb_node;
    struct binder_node *node;

    while (n) {
        node = rb_entry(n, struct binder_node, rb_node);

        if (ptr < node->ptr)
            n = n->rb_left;
        else if (ptr > node->ptr)
            n = n->rb_right;
        else
            return node;
    }
    return NULL;
}

static struct binder_node *binder_new_node(struct binder_proc *proc,
                       binder_uintptr_t ptr,
                       binder_uintptr_t cookie)
{
    struct rb_node **p = &proc->nodes.rb_node;
    struct rb_node *parent = NULL;
    struct binder_node *node;

    while (*p) {
        parent = *p;
        node = rb_entry(parent, struct binder_node, rb_node);

        if (ptr < node->ptr)
            p = &(*p)->rb_left;
        else if (ptr > node->ptr)
            p = &(*p)->rb_right;
        else
            return NULL;
    }

    node = kzalloc(sizeof(*node), GFP_KERNEL);
    if (node == NULL)
        return NULL;
    binder_stats_created(BINDER_STAT_NODE);
    rb_link_node(&node->rb_node, parent, p);
    rb_insert_color(&node->rb_node, &proc->nodes);
    node->debug_id = ++binder_last_id;
    node->proc = proc;
    node->ptr = ptr;
    node->cookie = cookie;
    node->work.type = BINDER_WORK_NODE;
    INIT_LIST_HEAD(&node->work.entry);
    INIT_LIST_HEAD(&node->async_todo);
    binder_debug(BINDER_DEBUG_INTERNAL_REFS,
             "%d:%d node %d u%016llx c%016llx created\n",
             proc->pid, current->pid, node->debug_id,
             (u64)node->ptr, (u64)node->cookie);
    return node;
}

static int binder_inc_node(struct binder_node *node, int strong, int internal,
               struct list_head *target_list)
{
    if (strong) {
        if (internal) {
            if (target_list == NULL &&
                node->internal_strong_refs == 0 &&
                !(node->proc &&
                  node == node->proc->context->binder_context_mgr_node &&
                  node->has_strong_ref)) {
                pr_err("invalid inc strong node for %d\n",
                    node->debug_id);
                return -EINVAL;
            }
            node->internal_strong_refs++;
        } else
            node->local_strong_refs++;
        if (!node->has_strong_ref && target_list) {
            list_del_init(&node->work.entry);
            list_add_tail(&node->work.entry, target_list);
        }
    } else {
        if (!internal)
            node->local_weak_refs++;
        if (!node->has_weak_ref && list_empty(&node->work.entry)) {
            if (target_list == NULL) {
                pr_err("invalid inc weak node for %d\n",
                    node->debug_id);
                return -EINVAL;
            }
            list_add_tail(&node->work.entry, target_list);
        }
    }
    return 0;
}

static int binder_dec_node(struct binder_node *node, int strong, int internal)
{
    if (strong) {
        if (internal)
            node->internal_strong_refs--;
        else
            node->local_strong_refs--;
        if (node->local_strong_refs || node->internal_strong_refs)
            return 0;
    } else {
        if (!internal)
            node->local_weak_refs--;
        if (node->local_weak_refs || !hlist_empty(&node->refs))
            return 0;
    }
    if (node->proc && (node->has_strong_ref || node->has_weak_ref)) {
        if (list_empty(&node->work.entry)) {
            list_add_tail(&node->work.entry, &node->proc->todo);
            wake_up_interruptible(&node->proc->wait);
        }
    } else {
        if (hlist_empty(&node->refs) && !node->local_strong_refs &&
            !node->local_weak_refs) {
            list_del_init(&node->work.entry);
            if (node->proc) {
                rb_erase(&node->rb_node, &node->proc->nodes);
                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                         "refless node %d deleted\n",
                         node->debug_id);
            } else {
                hlist_del(&node->dead_node);
                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                         "dead node %d deleted\n",
                         node->debug_id);
            }
            kfree(node);
            binder_stats_deleted(BINDER_STAT_NODE);
        }
    }

    return 0;
}


static struct binder_ref *binder_get_ref(struct binder_proc *proc,
                     u32 desc, bool need_strong_ref)
{
    struct rb_node *n = proc->refs_by_desc.rb_node;
    struct binder_ref *ref;

    while (n) {
        ref = rb_entry(n, struct binder_ref, rb_node_desc);

        if (desc < ref->desc) {
            n = n->rb_left;
        } else if (desc > ref->desc) {
            n = n->rb_right;
        } else if (need_strong_ref && !ref->strong) {
            binder_user_error("tried to use weak ref as strong ref\n");
            return NULL;
        } else {
            return ref;
        }
    }
    return NULL;
}

static struct binder_ref *binder_get_ref_for_node(struct binder_proc *proc,
                          struct binder_node *node)
{
    struct rb_node *n;
    struct rb_node **p = &proc->refs_by_node.rb_node;
    struct rb_node *parent = NULL;
    struct binder_ref *ref, *new_ref;
    struct binder_context *context = proc->context;

    while (*p) {
        parent = *p;
        ref = rb_entry(parent, struct binder_ref, rb_node_node);

        if (node < ref->node)
            p = &(*p)->rb_left;
        else if (node > ref->node)
            p = &(*p)->rb_right;
        else
            return ref;
    }
    new_ref = kzalloc(sizeof(*ref), GFP_KERNEL);
    if (new_ref == NULL)
        return NULL;
    binder_stats_created(BINDER_STAT_REF);
    new_ref->debug_id = ++binder_last_id;
    new_ref->proc = proc;
    new_ref->node = node;
    rb_link_node(&new_ref->rb_node_node, parent, p);
    rb_insert_color(&new_ref->rb_node_node, &proc->refs_by_node);

    new_ref->desc = (node == context->binder_context_mgr_node) ? 0 : 1;
    for (n = rb_first(&proc->refs_by_desc); n != NULL; n = rb_next(n)) {
        ref = rb_entry(n, struct binder_ref, rb_node_desc);
        if (ref->desc > new_ref->desc)
            break;
        new_ref->desc = ref->desc + 1;
    }

    p = &proc->refs_by_desc.rb_node;
    while (*p) {
        parent = *p;
        ref = rb_entry(parent, struct binder_ref, rb_node_desc);

        if (new_ref->desc < ref->desc)
            p = &(*p)->rb_left;
        else if (new_ref->desc > ref->desc)
            p = &(*p)->rb_right;
        else
            BUG();
    }
    rb_link_node(&new_ref->rb_node_desc, parent, p);
    rb_insert_color(&new_ref->rb_node_desc, &proc->refs_by_desc);
    if (node) {
        hlist_add_head(&new_ref->node_entry, &node->refs);

        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                 "%d new ref %d desc %d for node %d\n",
                  proc->pid, new_ref->debug_id, new_ref->desc,
                  node->debug_id);
    } else {
        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                 "%d new ref %d desc %d for dead node\n",
                  proc->pid, new_ref->debug_id, new_ref->desc);
    }
    return new_ref;
}

static void binder_delete_ref(struct binder_ref *ref)
{
    binder_debug(BINDER_DEBUG_INTERNAL_REFS,
             "%d delete ref %d desc %d for node %d\n",
              ref->proc->pid, ref->debug_id, ref->desc,
              ref->node->debug_id);

    rb_erase(&ref->rb_node_desc, &ref->proc->refs_by_desc);
    rb_erase(&ref->rb_node_node, &ref->proc->refs_by_node);
    if (ref->strong)
        binder_dec_node(ref->node, 1, 1);
    hlist_del(&ref->node_entry);
    binder_dec_node(ref->node, 0, 1);
    if (ref->death) {
        binder_debug(BINDER_DEBUG_DEAD_BINDER,
                 "%d delete ref %d desc %d has death notification\n",
                  ref->proc->pid, ref->debug_id, ref->desc);
        list_del(&ref->death->work.entry);
        kfree(ref->death);
        binder_stats_deleted(BINDER_STAT_DEATH);
    }
    kfree(ref);
    binder_stats_deleted(BINDER_STAT_REF);
}

static int binder_inc_ref(struct binder_ref *ref, int strong,
              struct list_head *target_list)
{
    int ret;

    if (strong) {
        if (ref->strong == 0) {
            ret = binder_inc_node(ref->node, 1, 1, target_list);
            if (ret)
                return ret;
        }
        ref->strong++;
    } else {
        if (ref->weak == 0) {
            ret = binder_inc_node(ref->node, 0, 1, target_list);
            if (ret)
                return ret;
        }
        ref->weak++;
    }
    return 0;
}


static int binder_dec_ref(struct binder_ref *ref, int strong)
{
    if (strong) {
        if (ref->strong == 0) {
            binder_user_error("%d invalid dec strong, ref %d desc %d s %d w %d\n",
                      ref->proc->pid, ref->debug_id,
                      ref->desc, ref->strong, ref->weak);
            return -EINVAL;
        }
        ref->strong--;
        if (ref->strong == 0) {
            int ret;

            ret = binder_dec_node(ref->node, strong, 1);
            if (ret)
                return ret;
        }
    } else {
        if (ref->weak == 0) {
            binder_user_error("%d invalid dec weak, ref %d desc %d s %d w %d\n",
                      ref->proc->pid, ref->debug_id,
                      ref->desc, ref->strong, ref->weak);
            return -EINVAL;
        }
        ref->weak--;
    }
    if (ref->strong == 0 && ref->weak == 0)
        binder_delete_ref(ref);
    return 0;
}

static void binder_pop_transaction(struct binder_thread *target_thread,
                   struct binder_transaction *t)
{
    if (target_thread) {
        BUG_ON(target_thread->transaction_stack != t);
        BUG_ON(target_thread->transaction_stack->from != target_thread);
        target_thread->transaction_stack =
            target_thread->transaction_stack->from_parent;
        t->from = NULL;
    }
    t->need_reply = 0;
    if (t->buffer)
        t->buffer->transaction = NULL;
    kfree(t);
    binder_stats_deleted(BINDER_STAT_TRANSACTION);
}

static void binder_send_failed_reply(struct binder_transaction *t,
                     uint32_t error_code)
{
    struct binder_thread *target_thread;
    struct binder_transaction *next;

    BUG_ON(t->flags & TF_ONE_WAY);
    while (1) {
        target_thread = t->from;
        if (target_thread) {
            if (target_thread->return_error != BR_OK &&
               target_thread->return_error2 == BR_OK) {
                target_thread->return_error2 =
                    target_thread->return_error;
                target_thread->return_error = BR_OK;
            }
            if (target_thread->return_error == BR_OK) {
                binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                         "send failed reply for transaction %d to %d:%d\n",
                          t->debug_id,
                          target_thread->proc->pid,
                          target_thread->pid);

                binder_pop_transaction(target_thread, t);
                target_thread->return_error = error_code;
                wake_up_interruptible(&target_thread->wait);
            } else {
                pr_err("reply failed, target thread, %d:%d, has error code %d already\n",
                    target_thread->proc->pid,
                    target_thread->pid,
                    target_thread->return_error);
            }
            return;
        }
        next = t->from_parent;

        binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                 "send failed reply for transaction %d, target dead\n",
                 t->debug_id);

        binder_pop_transaction(target_thread, t);
        if (next == NULL) {
            binder_debug(BINDER_DEBUG_DEAD_BINDER,
                     "reply failed, no target thread at root\n");
            return;
        }
        t = next;
        binder_debug(BINDER_DEBUG_DEAD_BINDER,
                 "reply failed, no target thread -- retry %d\n",
                  t->debug_id);
    }
}

/**
 * binder_validate_object() - checks for a valid metadata object in a buffer.
 * @buffer: binder_buffer that we're parsing.
 * @offset: offset in the buffer at which to validate an object.
 *
 * Return:  If there's a valid metadata object at @offset in @buffer, the
 *      size of that object. Otherwise, it returns zero.
 */
static size_t binder_validate_object(struct binder_buffer *buffer, u64 offset)
{
    /* Check if we can read a header first */
    struct binder_object_header *hdr;
    size_t object_size = 0;

    if (offset > buffer->data_size - sizeof(*hdr) ||
        buffer->data_size < sizeof(*hdr) ||
        !IS_ALIGNED(offset, sizeof(u32)))
        return 0;

    /* Ok, now see if we can read a complete object. */
    hdr = (struct binder_object_header *)(buffer->data + offset);
    switch (hdr->type) {
    case BINDER_TYPE_BINDER:
    case BINDER_TYPE_WEAK_BINDER:
    case BINDER_TYPE_HANDLE:
    case BINDER_TYPE_WEAK_HANDLE:
        object_size = sizeof(struct flat_binder_object);
        break;
    case BINDER_TYPE_FD:
        object_size = sizeof(struct binder_fd_object);
        break;
    case BINDER_TYPE_PTR:
        object_size = sizeof(struct binder_buffer_object);
        break;
    case BINDER_TYPE_FDA:
        object_size = sizeof(struct binder_fd_array_object);
        break;
    default:
        return 0;
    }
    if (offset <= buffer->data_size - object_size &&
        buffer->data_size >= object_size)
        return object_size;
    else
        return 0;
}

/**
 * binder_validate_ptr() - validates binder_buffer_object in a binder_buffer.
 * @b:      binder_buffer containing the object
 * @index:  index in offset array at which the binder_buffer_object is
 *      located
 * @start:  points to the start of the offset array
 * @num_valid:  the number of valid offsets in the offset array
 *
 * Return:  If @index is within the valid range of the offset array
 *      described by @start and @num_valid, and if there's a valid
 *      binder_buffer_object at the offset found in index @index
 *      of the offset array, that object is returned. Otherwise,
 *      %NULL is returned.
 *      Note that the offset found in index @index itself is not
 *      verified; this function assumes that @num_valid elements
 *      from @start were previously verified to have valid offsets.
 */
static struct binder_buffer_object *binder_validate_ptr(struct binder_buffer *b,
                            binder_size_t index,
                            binder_size_t *start,
                            binder_size_t num_valid)
{
    struct binder_buffer_object *buffer_obj;
    binder_size_t *offp;

    if (index >= num_valid)
        return NULL;

    offp = start + index;
    buffer_obj = (struct binder_buffer_object *)(b->data + *offp);
    if (buffer_obj->hdr.type != BINDER_TYPE_PTR)
        return NULL;

    return buffer_obj;
}

/**
 * binder_validate_fixup() - validates pointer/fd fixups happen in order.
 * @b:          transaction buffer
 * @objects_start   start of objects buffer
 * @buffer:     binder_buffer_object in which to fix up
 * @offset:     start offset in @buffer to fix up
 * @last_obj:       last binder_buffer_object that we fixed up in
 * @last_min_offset:    minimum fixup offset in @last_obj
 *
 * Return:      %true if a fixup in buffer @buffer at offset @offset is
 *          allowed.
 *
 * For safety reasons, we only allow fixups inside a buffer to happen
 * at increasing offsets; additionally, we only allow fixup on the last
 * buffer object that was verified, or one of its parents.
 *
 * Example of what is allowed:
 *
 * A
 *   B (parent = A, offset = 0)
 *   C (parent = A, offset = 16)
 *     D (parent = C, offset = 0)
 *   E (parent = A, offset = 32) // min_offset is 16 (C.parent_offset)
 *
 * Examples of what is not allowed:
 *
 * Decreasing offsets within the same parent:
 * A
 *   C (parent = A, offset = 16)
 *   B (parent = A, offset = 0) // decreasing offset within A
 *
 * Referring to a parent that wasn't the last object or any of its parents:
 * A
 *   B (parent = A, offset = 0)
 *   C (parent = A, offset = 0)
 *   C (parent = A, offset = 16)
 *     D (parent = B, offset = 0) // B is not A or any of A's parents
 */
static bool binder_validate_fixup(struct binder_buffer *b,
                  binder_size_t *objects_start,
                  struct binder_buffer_object *buffer,
                  binder_size_t fixup_offset,
                  struct binder_buffer_object *last_obj,
                  binder_size_t last_min_offset)
{
    if (!last_obj) {
        /* Nothing to fix up in */
        return false;
    }

    while (last_obj != buffer) {
        /*
         * Safe to retrieve the parent of last_obj, since it
         * was already previously verified by the driver.
         */
        if ((last_obj->flags & BINDER_BUFFER_FLAG_HAS_PARENT) == 0)
            return false;
        last_min_offset = last_obj->parent_offset + sizeof(uintptr_t);
        last_obj = (struct binder_buffer_object *)
            (b->data + *(objects_start + last_obj->parent));
    }
    return (fixup_offset >= last_min_offset);
}

static void binder_transaction_buffer_release(struct binder_proc *proc,
                          struct binder_buffer *buffer,
                          binder_size_t *failed_at)
{
    binder_size_t *offp, *off_start, *off_end;
    int debug_id = buffer->debug_id;

    binder_debug(BINDER_DEBUG_TRANSACTION,
             "%d buffer release %d, size %zd-%zd, failed at %p\n",
             proc->pid, buffer->debug_id,
             buffer->data_size, buffer->offsets_size, failed_at);

    if (buffer->target_node)
        binder_dec_node(buffer->target_node, 1, 0);

    off_start = (binder_size_t *)(buffer->data +
                      ALIGN(buffer->data_size, sizeof(void *)));
    if (failed_at)
        off_end = failed_at;
    else
        off_end = (void *)off_start + buffer->offsets_size;
    for (offp = off_start; offp < off_end; offp++) {
        struct binder_object_header *hdr;
        size_t object_size = binder_validate_object(buffer, *offp);

        if (object_size == 0) {
            pr_err("transaction release %d bad object at offset %lld, size %zd\n",
                   debug_id, (u64)*offp, buffer->data_size);
            continue;
        }
        hdr = (struct binder_object_header *)(buffer->data + *offp);
        switch (hdr->type) {
        case BINDER_TYPE_BINDER:
        case BINDER_TYPE_WEAK_BINDER: {
            struct flat_binder_object *fp;
            struct binder_node *node;

            fp = to_flat_binder_object(hdr);
            node = binder_get_node(proc, fp->binder);
            if (node == NULL) {
                pr_err("transaction release %d bad node %016llx\n",
                       debug_id, (u64)fp->binder);
                break;
            }
            binder_debug(BINDER_DEBUG_TRANSACTION,
                     "        node %d u%016llx\n",
                     node->debug_id, (u64)node->ptr);
            binder_dec_node(node, hdr->type == BINDER_TYPE_BINDER,
                    0);
        } break;
        case BINDER_TYPE_HANDLE:
        case BINDER_TYPE_WEAK_HANDLE: {
            struct flat_binder_object *fp;
            struct binder_ref *ref;

            fp = to_flat_binder_object(hdr);
            ref = binder_get_ref(proc, fp->handle,
                         hdr->type == BINDER_TYPE_HANDLE);
            if (ref == NULL) {
                pr_err("transaction release %d bad handle %d\n",
                 debug_id, fp->handle);
                break;
            }
            binder_debug(BINDER_DEBUG_TRANSACTION,
                     "        ref %d desc %d (node %d)\n",
                     ref->debug_id, ref->desc, ref->node->debug_id);
            binder_dec_ref(ref, hdr->type == BINDER_TYPE_HANDLE);
        } break;

        case BINDER_TYPE_FD: {
            struct binder_fd_object *fp = to_binder_fd_object(hdr);

            binder_debug(BINDER_DEBUG_TRANSACTION,
                     "        fd %d\n", fp->fd);
            if (failed_at)
                task_close_fd(proc, fp->fd);
        } break;
        case BINDER_TYPE_PTR:
            /*
             * Nothing to do here, this will get cleaned up when the
             * transaction buffer gets freed
             */
            break;
        case BINDER_TYPE_FDA: {
            struct binder_fd_array_object *fda;
            struct binder_buffer_object *parent;
            uintptr_t parent_buffer;
            u32 *fd_array;
            size_t fd_index;
            binder_size_t fd_buf_size;

            fda = to_binder_fd_array_object(hdr);
            parent = binder_validate_ptr(buffer, fda->parent,
                             off_start,
                             offp - off_start);
            if (!parent) {
                pr_err("transaction release %d bad parent offset",
                       debug_id);
                continue;
            }
            /*
             * Since the parent was already fixed up, convert it
             * back to kernel address space to access it
             */
            parent_buffer = parent->buffer -
                proc->user_buffer_offset;

            fd_buf_size = sizeof(u32) * fda->num_fds;
            if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
                pr_err("transaction release %d invalid number of fds (%lld)\n",
                       debug_id, (u64)fda->num_fds);
                continue;
            }
            if (fd_buf_size > parent->length ||
                fda->parent_offset > parent->length - fd_buf_size) {
                /* No space for all file descriptors here. */
                pr_err("transaction release %d not enough space for %lld fds in buffer\n",
                       debug_id, (u64)fda->num_fds);
                continue;
            }
            fd_array = (u32 *)(parent_buffer + fda->parent_offset);
            for (fd_index = 0; fd_index < fda->num_fds; fd_index++)
                task_close_fd(proc, fd_array[fd_index]);
        } break;
        default:
            pr_err("transaction release %d bad object type %x\n",
                debug_id, hdr->type);
            break;
        }
    }
}

static int binder_translate_binder(struct flat_binder_object *fp,
                   struct binder_transaction *t,
                   struct binder_thread *thread)
{
    struct binder_node *node;
    struct binder_ref *ref;
    struct binder_proc *proc = thread->proc;
    struct binder_proc *target_proc = t->to_proc;

    node = binder_get_node(proc, fp->binder);
    if (!node) {
        node = binder_new_node(proc, fp->binder, fp->cookie);
        if (!node)
            return -ENOMEM;

        node->min_priority = fp->flags & FLAT_BINDER_FLAG_PRIORITY_MASK;
        node->accept_fds = !!(fp->flags & FLAT_BINDER_FLAG_ACCEPTS_FDS);
    }
    if (fp->cookie != node->cookie) {
        binder_user_error("%d:%d sending u%016llx node %d, cookie mismatch %016llx != %016llx\n",
                  proc->pid, thread->pid, (u64)fp->binder,
                  node->debug_id, (u64)fp->cookie,
                  (u64)node->cookie);
        return -EINVAL;
    }
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 0, 0)
    if (security_binder_transfer_binder(proc->tsk, target_proc->tsk))
        return -EPERM;
#endif

    ref = binder_get_ref_for_node(target_proc, node);
    if (!ref)
        return -EINVAL;

    if (fp->hdr.type == BINDER_TYPE_BINDER)
        fp->hdr.type = BINDER_TYPE_HANDLE;
    else
        fp->hdr.type = BINDER_TYPE_WEAK_HANDLE;
    fp->binder = 0;
    fp->handle = ref->desc;
    fp->cookie = 0;
    binder_inc_ref(ref, fp->hdr.type == BINDER_TYPE_HANDLE, &thread->todo);

    trace_binder_transaction_node_to_ref(t, node, ref);
    binder_debug(BINDER_DEBUG_TRANSACTION,
             "        node %d u%016llx -> ref %d desc %d\n",
             node->debug_id, (u64)node->ptr,
             ref->debug_id, ref->desc);

    return 0;
}

static int binder_translate_handle(struct flat_binder_object *fp,
                   struct binder_transaction *t,
                   struct binder_thread *thread)
{
    struct binder_ref *ref;
    struct binder_proc *proc = thread->proc;
    struct binder_proc *target_proc = t->to_proc;

    ref = binder_get_ref(proc, fp->handle,
                 fp->hdr.type == BINDER_TYPE_HANDLE);
    if (!ref) {
        binder_user_error("%d:%d got transaction with invalid handle, %d\n",
                  proc->pid, thread->pid, fp->handle);
        return -EINVAL;
    }
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 0, 0)
    if (security_binder_transfer_binder(proc->tsk, target_proc->tsk))
        return -EPERM;
#endif

    if (ref->node->proc == target_proc) {
        if (fp->hdr.type == BINDER_TYPE_HANDLE)
            fp->hdr.type = BINDER_TYPE_BINDER;
        else
            fp->hdr.type = BINDER_TYPE_WEAK_BINDER;
        fp->binder = ref->node->ptr;
        fp->cookie = ref->node->cookie;
        binder_inc_node(ref->node, fp->hdr.type == BINDER_TYPE_BINDER,
                0, NULL);
        trace_binder_transaction_ref_to_node(t, ref);
        binder_debug(BINDER_DEBUG_TRANSACTION,
                 "        ref %d desc %d -> node %d u%016llx\n",
                 ref->debug_id, ref->desc, ref->node->debug_id,
                 (u64)ref->node->ptr);
    } else {
        struct binder_ref *new_ref;

        new_ref = binder_get_ref_for_node(target_proc, ref->node);
        if (!new_ref)
            return -EINVAL;

        fp->binder = 0;
        fp->handle = new_ref->desc;
        fp->cookie = 0;
        binder_inc_ref(new_ref, fp->hdr.type == BINDER_TYPE_HANDLE,
                   NULL);
        trace_binder_transaction_ref_to_ref(t, ref, new_ref);
        binder_debug(BINDER_DEBUG_TRANSACTION,
                 "        ref %d desc %d -> ref %d desc %d (node %d)\n",
                 ref->debug_id, ref->desc, new_ref->debug_id,
                 new_ref->desc, ref->node->debug_id);
    }
    return 0;
}

static int binder_translate_fd(int fd,
                   struct binder_transaction *t,
                   struct binder_thread *thread,
                   struct binder_transaction *in_reply_to)
{
    struct binder_proc *proc = thread->proc;
    struct binder_proc *target_proc = t->to_proc;
    int target_fd;
    struct file *file;
    int ret;
    bool target_allows_fd;

    if (in_reply_to)
        target_allows_fd = !!(in_reply_to->flags & TF_ACCEPT_FDS);
    else
        target_allows_fd = t->buffer->target_node->accept_fds;
    if (!target_allows_fd) {
        binder_user_error("%d:%d got %s with fd, %d, but target does not allow fds\n",
                  proc->pid, thread->pid,
                  in_reply_to ? "reply" : "transaction",
                  fd);
        ret = -EPERM;
        goto err_fd_not_accepted;
    }

    file = fget(fd);
    if (!file) {
        binder_user_error("%d:%d got transaction with invalid fd, %d\n",
                  proc->pid, thread->pid, fd);
        ret = -EBADF;
        goto err_fget;
    }
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 0, 0)
    ret = security_binder_transfer_file(proc->tsk, target_proc->tsk, file);
    if (ret < 0) {
        ret = -EPERM;
        goto err_security;
    }
#endif

    target_fd = task_get_unused_fd_flags(target_proc, O_CLOEXEC);
    if (target_fd < 0) {
        ret = -ENOMEM;
        goto err_get_unused_fd;
    }
    task_fd_install(target_proc, target_fd, file);
    trace_binder_transaction_fd(t, fd, target_fd);
    binder_debug(BINDER_DEBUG_TRANSACTION, "        fd %d -> %d\n",
             fd, target_fd);

    return target_fd;

err_get_unused_fd:
err_security:
    fput(file);
err_fget:
err_fd_not_accepted:
    return ret;
}

static int binder_translate_fd_array(struct binder_fd_array_object *fda,
                     struct binder_buffer_object *parent,
                     struct binder_transaction *t,
                     struct binder_thread *thread,
                     struct binder_transaction *in_reply_to)
{
    binder_size_t fdi, fd_buf_size, num_installed_fds;
    int target_fd;
    uintptr_t parent_buffer;
    u32 *fd_array;
    struct binder_proc *proc = thread->proc;
    struct binder_proc *target_proc = t->to_proc;

    fd_buf_size = sizeof(u32) * fda->num_fds;
    if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
        binder_user_error("%d:%d got transaction with invalid number of fds (%lld)\n",
                  proc->pid, thread->pid, (u64)fda->num_fds);
        return -EINVAL;
    }
    if (fd_buf_size > parent->length ||
        fda->parent_offset > parent->length - fd_buf_size) {
        /* No space for all file descriptors here. */
        binder_user_error("%d:%d not enough space to store %lld fds in buffer\n",
                  proc->pid, thread->pid, (u64)fda->num_fds);
        return -EINVAL;
    }
    /*
     * Since the parent was already fixed up, convert it
     * back to the kernel address space to access it
     */
    parent_buffer = parent->buffer - target_proc->user_buffer_offset;
    fd_array = (u32 *)(parent_buffer + fda->parent_offset);
    if (!IS_ALIGNED((unsigned long)fd_array, sizeof(u32))) {
        binder_user_error("%d:%d parent offset not aligned correctly.\n",
                  proc->pid, thread->pid);
        return -EINVAL;
    }
    for (fdi = 0; fdi < fda->num_fds; fdi++) {
        target_fd = binder_translate_fd(fd_array[fdi], t, thread,
                        in_reply_to);
        if (target_fd < 0)
            goto err_translate_fd_failed;
        fd_array[fdi] = target_fd;
    }
    return 0;

err_translate_fd_failed:
    /*
     * Failed to allocate fd or security error, free fds
     * installed so far.
     */
    num_installed_fds = fdi;
    for (fdi = 0; fdi < num_installed_fds; fdi++)
        task_close_fd(target_proc, fd_array[fdi]);
    return target_fd;
}

static int binder_fixup_parent(struct binder_transaction *t,
                   struct binder_thread *thread,
                   struct binder_buffer_object *bp,
                   binder_size_t *off_start,
                   binder_size_t num_valid,
                   struct binder_buffer_object *last_fixup_obj,
                   binder_size_t last_fixup_min_off)
{
    struct binder_buffer_object *parent;
    u8 *parent_buffer;
    struct binder_buffer *b = t->buffer;
    struct binder_proc *proc = thread->proc;
    struct binder_proc *target_proc = t->to_proc;

    if (!(bp->flags & BINDER_BUFFER_FLAG_HAS_PARENT))
        return 0;

    parent = binder_validate_ptr(b, bp->parent, off_start, num_valid);
    if (!parent) {
        binder_user_error("%d:%d got transaction with invalid parent offset or type\n",
                  proc->pid, thread->pid);
        return -EINVAL;
    }

    if (!binder_validate_fixup(b, off_start,
                   parent, bp->parent_offset,
                   last_fixup_obj,
                   last_fixup_min_off)) {
        binder_user_error("%d:%d got transaction with out-of-order buffer fixup\n",
                  proc->pid, thread->pid);
        return -EINVAL;
    }

    if (parent->length < sizeof(binder_uintptr_t) ||
        bp->parent_offset > parent->length - sizeof(binder_uintptr_t)) {
        /* No space for a pointer here! */
        binder_user_error("%d:%d got transaction with invalid parent offset\n",
                  proc->pid, thread->pid);
        return -EINVAL;
    }
    parent_buffer = (u8 *)(parent->buffer -
                   target_proc->user_buffer_offset);
    *(binder_uintptr_t *)(parent_buffer + bp->parent_offset) = bp->buffer;

    return 0;
}

static void binder_transaction(struct binder_proc *proc,
                   struct binder_thread *thread,
                   struct binder_transaction_data *tr, int reply,
                   binder_size_t extra_buffers_size)
{
    int ret;
    struct binder_transaction *t;
    struct binder_work *tcomplete;
    binder_size_t *offp, *off_end, *off_start;
    binder_size_t off_min;
    u8 *sg_bufp, *sg_buf_end;
    struct binder_proc *target_proc;
    struct binder_thread *target_thread = NULL;
    struct binder_node *target_node = NULL;
    struct list_head *target_list;
    wait_queue_head_t *target_wait;
    struct binder_transaction *in_reply_to = NULL;
    struct binder_transaction_log_entry *e;
    uint32_t return_error;
    struct binder_buffer_object *last_fixup_obj = NULL;
    binder_size_t last_fixup_min_off = 0;
    struct binder_context *context = proc->context;

    e = binder_transaction_log_add(&binder_transaction_log);
    e->call_type = reply ? 2 : !!(tr->flags & TF_ONE_WAY);
    e->from_proc = proc->pid;
    e->from_thread = thread->pid;
    e->target_handle = tr->target.handle;
    e->data_size = tr->data_size;
    e->offsets_size = tr->offsets_size;
    e->context_name = proc->context->name;

    if (reply) {
        in_reply_to = thread->transaction_stack;
        if (in_reply_to == NULL) {
            binder_user_error("%d:%d got reply transaction with no transaction stack\n",
                      proc->pid, thread->pid);
            return_error = BR_FAILED_REPLY;
            goto err_empty_call_stack;
        }
        binder_set_nice(in_reply_to->saved_priority);
        if (in_reply_to->to_thread != thread) {
            binder_user_error("%d:%d got reply transaction with bad transaction stack, transaction %d has target %d:%d\n",
                proc->pid, thread->pid, in_reply_to->debug_id,
                in_reply_to->to_proc ?
                in_reply_to->to_proc->pid : 0,
                in_reply_to->to_thread ?
                in_reply_to->to_thread->pid : 0);
            return_error = BR_FAILED_REPLY;
            in_reply_to = NULL;
            goto err_bad_call_stack;
        }
        thread->transaction_stack = in_reply_to->to_parent;
        target_thread = in_reply_to->from;
        if (target_thread == NULL) {
            return_error = BR_DEAD_REPLY;
            goto err_dead_binder;
        }
        if (target_thread->transaction_stack != in_reply_to) {
            binder_user_error("%d:%d got reply transaction with bad target transaction stack %d, expected %d\n",
                proc->pid, thread->pid,
                target_thread->transaction_stack ?
                target_thread->transaction_stack->debug_id : 0,
                in_reply_to->debug_id);
            return_error = BR_FAILED_REPLY;
            in_reply_to = NULL;
            target_thread = NULL;
            goto err_dead_binder;
        }
        target_proc = target_thread->proc;
    } else {
        if (tr->target.handle) {
            struct binder_ref *ref;

            ref = binder_get_ref(proc, tr->target.handle, true);
            if (ref == NULL) {
                binder_user_error("%d:%d got transaction to invalid handle\n",
                    proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                goto err_invalid_target_handle;
            }
            target_node = ref->node;
        } else {
            target_node = context->binder_context_mgr_node;
            if (target_node == NULL) {
                return_error = BR_DEAD_REPLY;
                goto err_no_context_mgr_node;
            }
        }
        e->to_node = target_node->debug_id;
        target_proc = target_node->proc;
        if (target_proc == NULL) {
            return_error = BR_DEAD_REPLY;
            goto err_dead_binder;
        }
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 0, 0)
        if (security_binder_transaction(proc->tsk,
                        target_proc->tsk) < 0) {
            return_error = BR_FAILED_REPLY;
            goto err_invalid_target_handle;
        }
#endif
        if (!(tr->flags & TF_ONE_WAY) && thread->transaction_stack) {
            struct binder_transaction *tmp;

            tmp = thread->transaction_stack;
            if (tmp->to_thread != thread) {
                binder_user_error("%d:%d got new transaction with bad transaction stack, transaction %d has target %d:%d\n",
                    proc->pid, thread->pid, tmp->debug_id,
                    tmp->to_proc ? tmp->to_proc->pid : 0,
                    tmp->to_thread ?
                    tmp->to_thread->pid : 0);
                return_error = BR_FAILED_REPLY;
                goto err_bad_call_stack;
            }
            while (tmp) {
                if (tmp->from && tmp->from->proc == target_proc)
                    target_thread = tmp->from;
                tmp = tmp->from_parent;
            }
        }
    }
    if (target_thread) {
        e->to_thread = target_thread->pid;
        target_list = &target_thread->todo;
        target_wait = &target_thread->wait;
    } else {
        target_list = &target_proc->todo;
        target_wait = &target_proc->wait;
    }
    e->to_proc = target_proc->pid;

    /* TODO: reuse incoming transaction for reply */
    t = kzalloc(sizeof(*t), GFP_KERNEL);
    if (t == NULL) {
        return_error = BR_FAILED_REPLY;
        goto err_alloc_t_failed;
    }
    binder_stats_created(BINDER_STAT_TRANSACTION);

    tcomplete = kzalloc(sizeof(*tcomplete), GFP_KERNEL);
    if (tcomplete == NULL) {
        return_error = BR_FAILED_REPLY;
        goto err_alloc_tcomplete_failed;
    }
    binder_stats_created(BINDER_STAT_TRANSACTION_COMPLETE);

    t->debug_id = ++binder_last_id;
    e->debug_id = t->debug_id;

    if (reply)
        binder_debug(BINDER_DEBUG_TRANSACTION,
                 "%d:%d BC_REPLY %d -> %d:%d, data %016llx-%016llx size %lld-%lld-%lld\n",
                 proc->pid, thread->pid, t->debug_id,
                 target_proc->pid, target_thread->pid,
                 (u64)tr->data.ptr.buffer,
                 (u64)tr->data.ptr.offsets,
                 (u64)tr->data_size, (u64)tr->offsets_size,
                 (u64)extra_buffers_size);
    else
        binder_debug(BINDER_DEBUG_TRANSACTION,
                 "%d:%d BC_TRANSACTION %d -> %d - node %d, data %016llx-%016llx size %lld-%lld-%lld\n",
                 proc->pid, thread->pid, t->debug_id,
                 target_proc->pid, target_node->debug_id,
                 (u64)tr->data.ptr.buffer,
                 (u64)tr->data.ptr.offsets,
                 (u64)tr->data_size, (u64)tr->offsets_size,
                 (u64)extra_buffers_size);

    if (!reply && !(tr->flags & TF_ONE_WAY))
        t->from = thread;
    else
        t->from = NULL;
    t->sender_euid = task_euid(proc->tsk);
    t->to_proc = target_proc;
    t->to_thread = target_thread;
    t->code = tr->code;
    t->flags = tr->flags;
    t->priority = task_nice(current);

    trace_binder_transaction(reply, t, target_node);

    t->buffer = binder_alloc_buf(target_proc, tr->data_size,
        tr->offsets_size, extra_buffers_size,
        !reply && (t->flags & TF_ONE_WAY));
    if (t->buffer == NULL) {
        return_error = BR_FAILED_REPLY;
        goto err_binder_alloc_buf_failed;
    }
    t->buffer->allow_user_free = 0;
    t->buffer->debug_id = t->debug_id;
    t->buffer->transaction = t;
    t->buffer->target_node = target_node;
    trace_binder_transaction_alloc_buf(t->buffer);
    if (target_node)
        binder_inc_node(target_node, 1, 0, NULL);

    off_start = (binder_size_t *)(t->buffer->data +
                      ALIGN(tr->data_size, sizeof(void *)));
    offp = off_start;

    if (copy_from_user(t->buffer->data, (const void __user *)(uintptr_t)
               tr->data.ptr.buffer, tr->data_size)) {
        binder_user_error("%d:%d got transaction with invalid data ptr\n",
                proc->pid, thread->pid);
        return_error = BR_FAILED_REPLY;
        goto err_copy_data_failed;
    }
    if (copy_from_user(offp, (const void __user *)(uintptr_t)
               tr->data.ptr.offsets, tr->offsets_size)) {
        binder_user_error("%d:%d got transaction with invalid offsets ptr\n",
                proc->pid, thread->pid);
        return_error = BR_FAILED_REPLY;
        goto err_copy_data_failed;
    }
    if (!IS_ALIGNED(tr->offsets_size, sizeof(binder_size_t))) {
        binder_user_error("%d:%d got transaction with invalid offsets size, %lld\n",
                proc->pid, thread->pid, (u64)tr->offsets_size);
        return_error = BR_FAILED_REPLY;
        goto err_bad_offset;
    }
    if (!IS_ALIGNED(extra_buffers_size, sizeof(u64))) {
        binder_user_error("%d:%d got transaction with unaligned buffers size, %lld\n",
                  proc->pid, thread->pid,
                  (u64)extra_buffers_size);
        return_error = BR_FAILED_REPLY;
        goto err_bad_offset;
    }
    off_end = (void *)off_start + tr->offsets_size;
    sg_bufp = (u8 *)(PTR_ALIGN(off_end, sizeof(void *)));
    sg_buf_end = sg_bufp + extra_buffers_size;
    off_min = 0;
    for (; offp < off_end; offp++) {
        struct binder_object_header *hdr;
        size_t object_size = binder_validate_object(t->buffer, *offp);

        if (object_size == 0 || *offp < off_min) {
            binder_user_error("%d:%d got transaction with invalid offset (%lld, min %lld max %lld) or object.\n",
                      proc->pid, thread->pid, (u64)*offp,
                      (u64)off_min,
                      (u64)t->buffer->data_size);
            return_error = BR_FAILED_REPLY;
            goto err_bad_offset;
        }

        hdr = (struct binder_object_header *)(t->buffer->data + *offp);
        off_min = *offp + object_size;
        switch (hdr->type) {
        case BINDER_TYPE_BINDER:
        case BINDER_TYPE_WEAK_BINDER: {
            struct flat_binder_object *fp;

            fp = to_flat_binder_object(hdr);
            ret = binder_translate_binder(fp, t, thread);
            if (ret < 0) {
                return_error = BR_FAILED_REPLY;
                goto err_translate_failed;
            }
        } break;
        case BINDER_TYPE_HANDLE:
        case BINDER_TYPE_WEAK_HANDLE: {
            struct flat_binder_object *fp;

            fp = to_flat_binder_object(hdr);
            ret = binder_translate_handle(fp, t, thread);
            if (ret < 0) {
                return_error = BR_FAILED_REPLY;
                goto err_translate_failed;
            }
        } break;

        case BINDER_TYPE_FD: {
            struct binder_fd_object *fp = to_binder_fd_object(hdr);
            int target_fd = binder_translate_fd(fp->fd, t, thread,
                                in_reply_to);

            if (target_fd < 0) {
                return_error = BR_FAILED_REPLY;
                goto err_translate_failed;
            }
            fp->pad_binder = 0;
            fp->fd = target_fd;
        } break;
        case BINDER_TYPE_FDA: {
            struct binder_fd_array_object *fda =
                to_binder_fd_array_object(hdr);
            struct binder_buffer_object *parent =
                binder_validate_ptr(t->buffer, fda->parent,
                            off_start,
                            offp - off_start);
            if (!parent) {
                binder_user_error("%d:%d got transaction with invalid parent offset or type\n",
                          proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                goto err_bad_parent;
            }
            if (!binder_validate_fixup(t->buffer, off_start,
                           parent, fda->parent_offset,
                           last_fixup_obj,
                           last_fixup_min_off)) {
                binder_user_error("%d:%d got transaction with out-of-order buffer fixup\n",
                          proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                goto err_bad_parent;
            }
            ret = binder_translate_fd_array(fda, parent, t, thread,
                            in_reply_to);
            if (ret < 0) {
                return_error = BR_FAILED_REPLY;
                goto err_translate_failed;
            }
            last_fixup_obj = parent;
            last_fixup_min_off =
                fda->parent_offset + sizeof(u32) * fda->num_fds;
        } break;
        case BINDER_TYPE_PTR: {
            struct binder_buffer_object *bp =
                to_binder_buffer_object(hdr);
            size_t buf_left = sg_buf_end - sg_bufp;

            if (bp->length > buf_left) {
                binder_user_error("%d:%d got transaction with too large buffer\n",
                          proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                goto err_bad_offset;
            }
            if (copy_from_user(sg_bufp,
                       (const void __user *)(uintptr_t)
                       bp->buffer, bp->length)) {
                binder_user_error("%d:%d got transaction with invalid offsets ptr\n",
                          proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                goto err_copy_data_failed;
            }
            /* Fixup buffer pointer to target proc address space */
            bp->buffer = (uintptr_t)sg_bufp +
                target_proc->user_buffer_offset;
            sg_bufp += ALIGN(bp->length, sizeof(u64));

            ret = binder_fixup_parent(t, thread, bp, off_start,
                          offp - off_start,
                          last_fixup_obj,
                          last_fixup_min_off);
            if (ret < 0) {
                return_error = BR_FAILED_REPLY;
                goto err_translate_failed;
            }
            last_fixup_obj = bp;
            last_fixup_min_off = 0;
        } break;
        default:
            binder_user_error("%d:%d got transaction with invalid object type, %x\n",
                proc->pid, thread->pid, hdr->type);
            return_error = BR_FAILED_REPLY;
            goto err_bad_object_type;
        }
    }
    if (reply) {
        BUG_ON(t->buffer->async_transaction != 0);
        binder_pop_transaction(target_thread, in_reply_to);
    } else if (!(t->flags & TF_ONE_WAY)) {
        BUG_ON(t->buffer->async_transaction != 0);
        t->need_reply = 1;
        t->from_parent = thread->transaction_stack;
        thread->transaction_stack = t;
    } else {
        BUG_ON(target_node == NULL);
        BUG_ON(t->buffer->async_transaction != 1);
        if (target_node->has_async_transaction) {
            target_list = &target_node->async_todo;
            target_wait = NULL;
        } else
            target_node->has_async_transaction = 1;
    }
    t->work.type = BINDER_WORK_TRANSACTION;
    list_add_tail(&t->work.entry, target_list);
    tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE;
    list_add_tail(&tcomplete->entry, &thread->todo);
    if (target_wait) {
        if (reply || !(t->flags & TF_ONE_WAY))
            wake_up_interruptible_sync(target_wait);
        else
            wake_up_interruptible(target_wait);
    }
    return;

err_translate_failed:
err_bad_object_type:
err_bad_offset:
err_bad_parent:
err_copy_data_failed:
    trace_binder_transaction_failed_buffer_release(t->buffer);
    binder_transaction_buffer_release(target_proc, t->buffer, offp);
    t->buffer->transaction = NULL;
    binder_free_buf(target_proc, t->buffer);
err_binder_alloc_buf_failed:
    kfree(tcomplete);
    binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
err_alloc_tcomplete_failed:
    kfree(t);
    binder_stats_deleted(BINDER_STAT_TRANSACTION);
err_alloc_t_failed:
err_bad_call_stack:
err_empty_call_stack:
err_dead_binder:
err_invalid_target_handle:
err_no_context_mgr_node:
    binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
             "%d:%d transaction failed %d, size %lld-%lld\n",
             proc->pid, thread->pid, return_error,
             (u64)tr->data_size, (u64)tr->offsets_size);

    {
        struct binder_transaction_log_entry *fe;

        fe = binder_transaction_log_add(&binder_transaction_log_failed);
        *fe = *e;
    }

    BUG_ON(thread->return_error != BR_OK);
    if (in_reply_to) {
        thread->return_error = BR_TRANSACTION_COMPLETE;
        binder_send_failed_reply(in_reply_to, return_error);
    } else
        thread->return_error = return_error;
}

static int binder_thread_write(struct binder_proc *proc,
            struct binder_thread *thread,
            binder_uintptr_t binder_buffer, size_t size,
            binder_size_t *consumed)
{
    uint32_t cmd;
    struct binder_context *context = proc->context;
    void __user *buffer = (void __user *)(uintptr_t)binder_buffer;
    void __user *ptr = buffer + *consumed;
    void __user *end = buffer + size;

    while (ptr < end && thread->return_error == BR_OK) {
        if (get_user(cmd, (uint32_t __user *)ptr))
            return -EFAULT;
        ptr += sizeof(uint32_t);
        trace_binder_command(cmd);
        if (_IOC_NR(cmd) < ARRAY_SIZE(binder_stats.bc)) {
            binder_stats.bc[_IOC_NR(cmd)]++;
            proc->stats.bc[_IOC_NR(cmd)]++;
            thread->stats.bc[_IOC_NR(cmd)]++;
        }
        switch (cmd) {
        case BC_INCREFS:
        case BC_ACQUIRE:
        case BC_RELEASE:
        case BC_DECREFS: {
            uint32_t target;
            struct binder_ref *ref;
            const char *debug_string;

            if (get_user(target, (uint32_t __user *)ptr))
                return -EFAULT;
            ptr += sizeof(uint32_t);
            if (target == 0 && context->binder_context_mgr_node &&
                (cmd == BC_INCREFS || cmd == BC_ACQUIRE)) {
                ref = binder_get_ref_for_node(proc,
                    context->binder_context_mgr_node);
                if (ref->desc != target) {
                    binder_user_error("%d:%d tried to acquire reference to desc 0, got %d instead\n",
                        proc->pid, thread->pid,
                        ref->desc);
                }
            } else
                ref = binder_get_ref(proc, target,
                             cmd == BC_ACQUIRE ||
                             cmd == BC_RELEASE);
            if (ref == NULL) {
                binder_user_error("%d:%d refcount change on invalid ref %d\n",
                    proc->pid, thread->pid, target);
                break;
            }
            switch (cmd) {
            case BC_INCREFS:
                debug_string = "IncRefs";
                binder_inc_ref(ref, 0, NULL);
                break;
            case BC_ACQUIRE:
                debug_string = "Acquire";
                binder_inc_ref(ref, 1, NULL);
                break;
            case BC_RELEASE:
                debug_string = "Release";
                binder_dec_ref(ref, 1);
                break;
            case BC_DECREFS:
            default:
                debug_string = "DecRefs";
                binder_dec_ref(ref, 0);
                break;
            }
            binder_debug(BINDER_DEBUG_USER_REFS,
                     "%d:%d %s ref %d desc %d s %d w %d for node %d\n",
                     proc->pid, thread->pid, debug_string, ref->debug_id,
                     ref->desc, ref->strong, ref->weak, ref->node->debug_id);
            break;
        }
        case BC_INCREFS_DONE:
        case BC_ACQUIRE_DONE: {
            binder_uintptr_t node_ptr;
            binder_uintptr_t cookie;
            struct binder_node *node;

            if (get_user(node_ptr, (binder_uintptr_t __user *)ptr))
                return -EFAULT;
            ptr += sizeof(binder_uintptr_t);
            if (get_user(cookie, (binder_uintptr_t __user *)ptr))
                return -EFAULT;
            ptr += sizeof(binder_uintptr_t);
            node = binder_get_node(proc, node_ptr);
            if (node == NULL) {
                binder_user_error("%d:%d %s u%016llx no match\n",
                    proc->pid, thread->pid,
                    cmd == BC_INCREFS_DONE ?
                    "BC_INCREFS_DONE" :
                    "BC_ACQUIRE_DONE",
                    (u64)node_ptr);
                break;
            }
            if (cookie != node->cookie) {
                binder_user_error("%d:%d %s u%016llx node %d cookie mismatch %016llx != %016llx\n",
                    proc->pid, thread->pid,
                    cmd == BC_INCREFS_DONE ?
                    "BC_INCREFS_DONE" : "BC_ACQUIRE_DONE",
                    (u64)node_ptr, node->debug_id,
                    (u64)cookie, (u64)node->cookie);
                break;
            }
            if (cmd == BC_ACQUIRE_DONE) {
                if (node->pending_strong_ref == 0) {
                    binder_user_error("%d:%d BC_ACQUIRE_DONE node %d has no pending acquire request\n",
                        proc->pid, thread->pid,
                        node->debug_id);
                    break;
                }
                node->pending_strong_ref = 0;
            } else {
                if (node->pending_weak_ref == 0) {
                    binder_user_error("%d:%d BC_INCREFS_DONE node %d has no pending increfs request\n",
                        proc->pid, thread->pid,
                        node->debug_id);
                    break;
                }
                node->pending_weak_ref = 0;
            }
            binder_dec_node(node, cmd == BC_ACQUIRE_DONE, 0);
            binder_debug(BINDER_DEBUG_USER_REFS,
                     "%d:%d %s node %d ls %d lw %d\n",
                     proc->pid, thread->pid,
                     cmd == BC_INCREFS_DONE ? "BC_INCREFS_DONE" : "BC_ACQUIRE_DONE",
                     node->debug_id, node->local_strong_refs, node->local_weak_refs);
            break;
        }
        case BC_ATTEMPT_ACQUIRE:
            pr_err("BC_ATTEMPT_ACQUIRE not supported\n");
            return -EINVAL;
        case BC_ACQUIRE_RESULT:
            pr_err("BC_ACQUIRE_RESULT not supported\n");
            return -EINVAL;

        case BC_FREE_BUFFER: {
            binder_uintptr_t data_ptr;
            struct binder_buffer *buffer;

            if (get_user(data_ptr, (binder_uintptr_t __user *)ptr))
                return -EFAULT;
            ptr += sizeof(binder_uintptr_t);

            buffer = binder_buffer_lookup(proc, data_ptr);
            if (buffer == NULL) {
                binder_user_error("%d:%d BC_FREE_BUFFER u%016llx no match\n",
                    proc->pid, thread->pid, (u64)data_ptr);
                break;
            }
            if (!buffer->allow_user_free) {
                binder_user_error("%d:%d BC_FREE_BUFFER u%016llx matched unreturned buffer\n",
                    proc->pid, thread->pid, (u64)data_ptr);
                break;
            }
            binder_debug(BINDER_DEBUG_FREE_BUFFER,
                     "%d:%d BC_FREE_BUFFER u%016llx found buffer %d for %s transaction\n",
                     proc->pid, thread->pid, (u64)data_ptr,
                     buffer->debug_id,
                     buffer->transaction ? "active" : "finished");

            if (buffer->transaction) {
                buffer->transaction->buffer = NULL;
                buffer->transaction = NULL;
            }
            if (buffer->async_transaction && buffer->target_node) {
                BUG_ON(!buffer->target_node->has_async_transaction);
                if (list_empty(&buffer->target_node->async_todo))
                    buffer->target_node->has_async_transaction = 0;
                else
                    list_move_tail(buffer->target_node->async_todo.next, &thread->todo);
            }
            trace_binder_transaction_buffer_release(buffer);
            binder_transaction_buffer_release(proc, buffer, NULL);
            binder_free_buf(proc, buffer);
            break;
        }

        case BC_TRANSACTION_SG:
        case BC_REPLY_SG: {
            struct binder_transaction_data_sg tr;

            if (copy_from_user(&tr, ptr, sizeof(tr)))
                return -EFAULT;
            ptr += sizeof(tr);
            binder_transaction(proc, thread, &tr.transaction_data,
                       cmd == BC_REPLY_SG, tr.buffers_size);
            break;
        }
        case BC_TRANSACTION:
        case BC_REPLY: {
            struct binder_transaction_data tr;

            if (copy_from_user(&tr, ptr, sizeof(tr)))
                return -EFAULT;
            ptr += sizeof(tr);
            binder_transaction(proc, thread, &tr,
                       cmd == BC_REPLY, 0);
            break;
        }

        case BC_REGISTER_LOOPER:
            binder_debug(BINDER_DEBUG_THREADS,
                     "%d:%d BC_REGISTER_LOOPER\n",
                     proc->pid, thread->pid);
            if (thread->looper & BINDER_LOOPER_STATE_ENTERED) {
                thread->looper |= BINDER_LOOPER_STATE_INVALID;
                binder_user_error("%d:%d ERROR: BC_REGISTER_LOOPER called after BC_ENTER_LOOPER\n",
                    proc->pid, thread->pid);
            } else if (proc->requested_threads == 0) {
                thread->looper |= BINDER_LOOPER_STATE_INVALID;
                binder_user_error("%d:%d ERROR: BC_REGISTER_LOOPER called without request\n",
                    proc->pid, thread->pid);
            } else {
                proc->requested_threads--;
                proc->requested_threads_started++;
            }
            thread->looper |= BINDER_LOOPER_STATE_REGISTERED;
            break;
        case BC_ENTER_LOOPER:
            binder_debug(BINDER_DEBUG_THREADS,
                     "%d:%d BC_ENTER_LOOPER\n",
                     proc->pid, thread->pid);
            if (thread->looper & BINDER_LOOPER_STATE_REGISTERED) {
                thread->looper |= BINDER_LOOPER_STATE_INVALID;
                binder_user_error("%d:%d ERROR: BC_ENTER_LOOPER called after BC_REGISTER_LOOPER\n",
                    proc->pid, thread->pid);
            }
            thread->looper |= BINDER_LOOPER_STATE_ENTERED;
            break;
        case BC_EXIT_LOOPER:
            binder_debug(BINDER_DEBUG_THREADS,
                     "%d:%d BC_EXIT_LOOPER\n",
                     proc->pid, thread->pid);
            thread->looper |= BINDER_LOOPER_STATE_EXITED;
            break;

        case BC_REQUEST_DEATH_NOTIFICATION:
        case BC_CLEAR_DEATH_NOTIFICATION: {
            uint32_t target;
            binder_uintptr_t cookie;
            struct binder_ref *ref;
            struct binder_ref_death *death;

            if (get_user(target, (uint32_t __user *)ptr))
                return -EFAULT;
            ptr += sizeof(uint32_t);
            if (get_user(cookie, (binder_uintptr_t __user *)ptr))
                return -EFAULT;
            ptr += sizeof(binder_uintptr_t);
            ref = binder_get_ref(proc, target, false);
            if (ref == NULL) {
                binder_user_error("%d:%d %s invalid ref %d\n",
                    proc->pid, thread->pid,
                    cmd == BC_REQUEST_DEATH_NOTIFICATION ?
                    "BC_REQUEST_DEATH_NOTIFICATION" :
                    "BC_CLEAR_DEATH_NOTIFICATION",
                    target);
                break;
            }

            binder_debug(BINDER_DEBUG_DEATH_NOTIFICATION,
                     "%d:%d %s %016llx ref %d desc %d s %d w %d for node %d\n",
                     proc->pid, thread->pid,
                     cmd == BC_REQUEST_DEATH_NOTIFICATION ?
                     "BC_REQUEST_DEATH_NOTIFICATION" :
                     "BC_CLEAR_DEATH_NOTIFICATION",
                     (u64)cookie, ref->debug_id, ref->desc,
                     ref->strong, ref->weak, ref->node->debug_id);

            if (cmd == BC_REQUEST_DEATH_NOTIFICATION) {
                if (ref->death) {
                    binder_user_error("%d:%d BC_REQUEST_DEATH_NOTIFICATION death notification already set\n",
                        proc->pid, thread->pid);
                    break;
                }
                death = kzalloc(sizeof(*death), GFP_KERNEL);
                if (death == NULL) {
                    thread->return_error = BR_ERROR;
                    binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                             "%d:%d BC_REQUEST_DEATH_NOTIFICATION failed\n",
                             proc->pid, thread->pid);
                    break;
                }
                binder_stats_created(BINDER_STAT_DEATH);
                INIT_LIST_HEAD(&death->work.entry);
                death->cookie = cookie;
                ref->death = death;
                if (ref->node->proc == NULL) {
                    ref->death->work.type = BINDER_WORK_DEAD_BINDER;
                    if (thread->looper & (BINDER_LOOPER_STATE_REGISTERED | BINDER_LOOPER_STATE_ENTERED)) {
                        list_add_tail(&ref->death->work.entry, &thread->todo);
                    } else {
                        list_add_tail(&ref->death->work.entry, &proc->todo);
                        wake_up_interruptible(&proc->wait);
                    }
                }
            } else {
                if (ref->death == NULL) {
                    binder_user_error("%d:%d BC_CLEAR_DEATH_NOTIFICATION death notification not active\n",
                        proc->pid, thread->pid);
                    break;
                }
                death = ref->death;
                if (death->cookie != cookie) {
                    binder_user_error("%d:%d BC_CLEAR_DEATH_NOTIFICATION death notification cookie mismatch %016llx != %016llx\n",
                        proc->pid, thread->pid,
                        (u64)death->cookie,
                        (u64)cookie);
                    break;
                }
                ref->death = NULL;
                if (list_empty(&death->work.entry)) {
                    death->work.type = BINDER_WORK_CLEAR_DEATH_NOTIFICATION;
                    if (thread->looper & (BINDER_LOOPER_STATE_REGISTERED | BINDER_LOOPER_STATE_ENTERED)) {
                        list_add_tail(&death->work.entry, &thread->todo);
                    } else {
                        list_add_tail(&death->work.entry, &proc->todo);
                        wake_up_interruptible(&proc->wait);
                    }
                } else {
                    BUG_ON(death->work.type != BINDER_WORK_DEAD_BINDER);
                    death->work.type = BINDER_WORK_DEAD_BINDER_AND_CLEAR;
                }
            }
        } break;
        case BC_DEAD_BINDER_DONE: {
            struct binder_work *w;
            binder_uintptr_t cookie;
            struct binder_ref_death *death = NULL;

            if (get_user(cookie, (binder_uintptr_t __user *)ptr))
                return -EFAULT;

            ptr += sizeof(cookie);
            list_for_each_entry(w, &proc->delivered_death, entry) {
                struct binder_ref_death *tmp_death = container_of(w, struct binder_ref_death, work);

                if (tmp_death->cookie == cookie) {
                    death = tmp_death;
                    break;
                }
            }
            binder_debug(BINDER_DEBUG_DEAD_BINDER,
                     "%d:%d BC_DEAD_BINDER_DONE %016llx found %p\n",
                     proc->pid, thread->pid, (u64)cookie,
                     death);
            if (death == NULL) {
                binder_user_error("%d:%d BC_DEAD_BINDER_DONE %016llx not found\n",
                    proc->pid, thread->pid, (u64)cookie);
                break;
            }

            list_del_init(&death->work.entry);
            if (death->work.type == BINDER_WORK_DEAD_BINDER_AND_CLEAR) {
                death->work.type = BINDER_WORK_CLEAR_DEATH_NOTIFICATION;
                if (thread->looper & (BINDER_LOOPER_STATE_REGISTERED | BINDER_LOOPER_STATE_ENTERED)) {
                    list_add_tail(&death->work.entry, &thread->todo);
                } else {
                    list_add_tail(&death->work.entry, &proc->todo);
                    wake_up_interruptible(&proc->wait);
                }
            }
        } break;

        default:
            pr_err("%d:%d unknown command %d\n",
                   proc->pid, thread->pid, cmd);
            return -EINVAL;
        }
        *consumed = ptr - buffer;
    }
    return 0;
}

static void binder_stat_br(struct binder_proc *proc,
               struct binder_thread *thread, uint32_t cmd)
{
    trace_binder_return(cmd);
    if (_IOC_NR(cmd) < ARRAY_SIZE(binder_stats.br)) {
        binder_stats.br[_IOC_NR(cmd)]++;
        proc->stats.br[_IOC_NR(cmd)]++;
        thread->stats.br[_IOC_NR(cmd)]++;
    }
}

static int binder_has_proc_work(struct binder_proc *proc,
                struct binder_thread *thread)
{
    return !list_empty(&proc->todo) ||
        (thread->looper & BINDER_LOOPER_STATE_NEED_RETURN);
}

static int binder_has_thread_work(struct binder_thread *thread)
{
    return !list_empty(&thread->todo) || thread->return_error != BR_OK ||
        (thread->looper & BINDER_LOOPER_STATE_NEED_RETURN);
}

static int binder_thread_read(struct binder_proc *proc,
                  struct binder_thread *thread,
                  binder_uintptr_t binder_buffer, size_t size,
                  binder_size_t *consumed, int non_block)
{
    void __user *buffer = (void __user *)(uintptr_t)binder_buffer;
    void __user *ptr = buffer + *consumed;
    void __user *end = buffer + size;

    int ret = 0;
    int wait_for_proc_work;

    if (*consumed == 0) {
        if (put_user(BR_NOOP, (uint32_t __user *)ptr))
            return -EFAULT;
        ptr += sizeof(uint32_t);
    }

retry:
    wait_for_proc_work = thread->transaction_stack == NULL &&
                list_empty(&thread->todo);

    if (thread->return_error != BR_OK && ptr < end) {
        if (thread->return_error2 != BR_OK) {
            if (put_user(thread->return_error2, (uint32_t __user *)ptr))
                return -EFAULT;
            ptr += sizeof(uint32_t);
            binder_stat_br(proc, thread, thread->return_error2);
            if (ptr == end)
                goto done;
            thread->return_error2 = BR_OK;
        }
        if (put_user(thread->return_error, (uint32_t __user *)ptr))
            return -EFAULT;
        ptr += sizeof(uint32_t);
        binder_stat_br(proc, thread, thread->return_error);
        thread->return_error = BR_OK;
        goto done;
    }


    thread->looper |= BINDER_LOOPER_STATE_WAITING;
    if (wait_for_proc_work)
        proc->ready_threads++;

    binder_unlock(__func__);

    trace_binder_wait_for_work(wait_for_proc_work,
                   !!thread->transaction_stack,
                   !list_empty(&thread->todo));
    if (wait_for_proc_work) {
        if (!(thread->looper & (BINDER_LOOPER_STATE_REGISTERED |
                    BINDER_LOOPER_STATE_ENTERED))) {
            binder_user_error("%d:%d ERROR: Thread waiting for process work before calling BC_REGISTER_LOOPER or BC_ENTER_LOOPER (state %x)\n",
                proc->pid, thread->pid, thread->looper);
            wait_event_interruptible(binder_user_error_wait,
                         binder_stop_on_user_error < 2);
        }
        binder_set_nice(proc->default_priority);
        if (non_block) {
            if (!binder_has_proc_work(proc, thread))
                ret = -EAGAIN;
        } else
            ret = wait_event_freezable_exclusive(proc->wait, binder_has_proc_work(proc, thread));
    } else {
        if (non_block) {
            if (!binder_has_thread_work(thread))
                ret = -EAGAIN;
        } else
            ret = wait_event_freezable(thread->wait, binder_has_thread_work(thread));
    }

    binder_lock(__func__);

    if (wait_for_proc_work)
        proc->ready_threads--;
    thread->looper &= ~BINDER_LOOPER_STATE_WAITING;

    if (ret)
        return ret;

    while (1) {
        uint32_t cmd;
        struct binder_transaction_data tr;
        struct binder_work *w;
        struct binder_transaction *t = NULL;

        if (!list_empty(&thread->todo)) {
            w = list_first_entry(&thread->todo, struct binder_work,
                         entry);
        } else if (!list_empty(&proc->todo) && wait_for_proc_work) {
            w = list_first_entry(&proc->todo, struct binder_work,
                         entry);
        } else {
            /* no data added */
            if (ptr - buffer == 4 &&
                !(thread->looper & BINDER_LOOPER_STATE_NEED_RETURN))
                goto retry;
            break;
        }

        if (end - ptr < sizeof(tr) + 4)
            break;

        switch (w->type) {
        case BINDER_WORK_TRANSACTION: {
            t = container_of(w, struct binder_transaction, work);
        } break;
        case BINDER_WORK_TRANSACTION_COMPLETE: {
            cmd = BR_TRANSACTION_COMPLETE;
            if (put_user(cmd, (uint32_t __user *)ptr))
                return -EFAULT;
            ptr += sizeof(uint32_t);

            binder_stat_br(proc, thread, cmd);
            binder_debug(BINDER_DEBUG_TRANSACTION_COMPLETE,
                     "%d:%d BR_TRANSACTION_COMPLETE\n",
                     proc->pid, thread->pid);

            list_del(&w->entry);
            kfree(w);
            binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
        } break;
        case BINDER_WORK_NODE: {
            struct binder_node *node = container_of(w, struct binder_node, work);
            uint32_t cmd = BR_NOOP;
            const char *cmd_name;
            int strong = node->internal_strong_refs || node->local_strong_refs;
            int weak = !hlist_empty(&node->refs) || node->local_weak_refs || strong;

            if (weak && !node->has_weak_ref) {
                cmd = BR_INCREFS;
                cmd_name = "BR_INCREFS";
                node->has_weak_ref = 1;
                node->pending_weak_ref = 1;
                node->local_weak_refs++;
            } else if (strong && !node->has_strong_ref) {
                cmd = BR_ACQUIRE;
                cmd_name = "BR_ACQUIRE";
                node->has_strong_ref = 1;
                node->pending_strong_ref = 1;
                node->local_strong_refs++;
            } else if (!strong && node->has_strong_ref) {
                cmd = BR_RELEASE;
                cmd_name = "BR_RELEASE";
                node->has_strong_ref = 0;
            } else if (!weak && node->has_weak_ref) {
                cmd = BR_DECREFS;
                cmd_name = "BR_DECREFS";
                node->has_weak_ref = 0;
            }
            if (cmd != BR_NOOP) {
                if (put_user(cmd, (uint32_t __user *)ptr))
                    return -EFAULT;
                ptr += sizeof(uint32_t);
                if (put_user(node->ptr,
                         (binder_uintptr_t __user *)ptr))
                    return -EFAULT;
                ptr += sizeof(binder_uintptr_t);
                if (put_user(node->cookie,
                         (binder_uintptr_t __user *)ptr))
                    return -EFAULT;
                ptr += sizeof(binder_uintptr_t);

                binder_stat_br(proc, thread, cmd);
                binder_debug(BINDER_DEBUG_USER_REFS,
                         "%d:%d %s %d u%016llx c%016llx\n",
                         proc->pid, thread->pid, cmd_name,
                         node->debug_id,
                         (u64)node->ptr, (u64)node->cookie);
            } else {
                list_del_init(&w->entry);
                if (!weak && !strong) {
                    binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                             "%d:%d node %d u%016llx c%016llx deleted\n",
                             proc->pid, thread->pid,
                             node->debug_id,
                             (u64)node->ptr,
                             (u64)node->cookie);
                    rb_erase(&node->rb_node, &proc->nodes);
                    kfree(node);
                    binder_stats_deleted(BINDER_STAT_NODE);
                } else {
                    binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                             "%d:%d node %d u%016llx c%016llx state unchanged\n",
                             proc->pid, thread->pid,
                             node->debug_id,
                             (u64)node->ptr,
                             (u64)node->cookie);
                }
            }
        } break;
        case BINDER_WORK_DEAD_BINDER:
        case BINDER_WORK_DEAD_BINDER_AND_CLEAR:
        case BINDER_WORK_CLEAR_DEATH_NOTIFICATION: {
            struct binder_ref_death *death;
            uint32_t cmd;

            death = container_of(w, struct binder_ref_death, work);
            if (w->type == BINDER_WORK_CLEAR_DEATH_NOTIFICATION)
                cmd = BR_CLEAR_DEATH_NOTIFICATION_DONE;
            else
                cmd = BR_DEAD_BINDER;
            if (put_user(cmd, (uint32_t __user *)ptr))
                return -EFAULT;
            ptr += sizeof(uint32_t);
            if (put_user(death->cookie,
                     (binder_uintptr_t __user *)ptr))
                return -EFAULT;
            ptr += sizeof(binder_uintptr_t);
            binder_stat_br(proc, thread, cmd);
            binder_debug(BINDER_DEBUG_DEATH_NOTIFICATION,
                     "%d:%d %s %016llx\n",
                      proc->pid, thread->pid,
                      cmd == BR_DEAD_BINDER ?
                      "BR_DEAD_BINDER" :
                      "BR_CLEAR_DEATH_NOTIFICATION_DONE",
                      (u64)death->cookie);

            if (w->type == BINDER_WORK_CLEAR_DEATH_NOTIFICATION) {
                list_del(&w->entry);
                kfree(death);
                binder_stats_deleted(BINDER_STAT_DEATH);
            } else
                list_move(&w->entry, &proc->delivered_death);
            if (cmd == BR_DEAD_BINDER)
                goto done; /* DEAD_BINDER notifications can cause transactions */
        } break;
        }

        if (!t)
            continue;

        BUG_ON(t->buffer == NULL);
        if (t->buffer->target_node) {
            struct binder_node *target_node = t->buffer->target_node;

            tr.target.ptr = target_node->ptr;
            tr.cookie =  target_node->cookie;
            t->saved_priority = task_nice(current);
            if (t->priority < target_node->min_priority &&
                !(t->flags & TF_ONE_WAY))
                binder_set_nice(t->priority);
            else if (!(t->flags & TF_ONE_WAY) ||
                 t->saved_priority > target_node->min_priority)
                binder_set_nice(target_node->min_priority);
            cmd = BR_TRANSACTION;
        } else {
            tr.target.ptr = 0;
            tr.cookie = 0;
            cmd = BR_REPLY;
        }
        tr.code = t->code;
        tr.flags = t->flags;
        tr.sender_euid = from_kuid(current_user_ns(), t->sender_euid);

        if (t->from) {
            struct task_struct *sender = t->from->proc->tsk;

            tr.sender_pid = task_tgid_nr_ns(sender,
                            task_active_pid_ns(current));
        } else {
            tr.sender_pid = 0;
        }

        tr.data_size = t->buffer->data_size;
        tr.offsets_size = t->buffer->offsets_size;
        tr.data.ptr.buffer = (binder_uintptr_t)(
                    (uintptr_t)t->buffer->data +
                    proc->user_buffer_offset);
        tr.data.ptr.offsets = tr.data.ptr.buffer +
                    ALIGN(t->buffer->data_size,
                        sizeof(void *));

        if (put_user(cmd, (uint32_t __user *)ptr))
            return -EFAULT;
        ptr += sizeof(uint32_t);
        if (copy_to_user(ptr, &tr, sizeof(tr)))
            return -EFAULT;
        ptr += sizeof(tr);

        trace_binder_transaction_received(t);
        binder_stat_br(proc, thread, cmd);
        binder_debug(BINDER_DEBUG_TRANSACTION,
                 "%d:%d %s %d %d:%d, cmd %d size %zd-%zd ptr %016llx-%016llx\n",
                 proc->pid, thread->pid,
                 (cmd == BR_TRANSACTION) ? "BR_TRANSACTION" :
                 "BR_REPLY",
                 t->debug_id, t->from ? t->from->proc->pid : 0,
                 t->from ? t->from->pid : 0, cmd,
                 t->buffer->data_size, t->buffer->offsets_size,
                 (u64)tr.data.ptr.buffer, (u64)tr.data.ptr.offsets);

        list_del(&t->work.entry);
        t->buffer->allow_user_free = 1;
        if (cmd == BR_TRANSACTION && !(t->flags & TF_ONE_WAY)) {
            t->to_parent = thread->transaction_stack;
            t->to_thread = thread;
            thread->transaction_stack = t;
        } else {
            t->buffer->transaction = NULL;
            kfree(t);
            binder_stats_deleted(BINDER_STAT_TRANSACTION);
        }
        break;
    }

done:

    *consumed = ptr - buffer;
    if (proc->requested_threads + proc->ready_threads == 0 &&
        proc->requested_threads_started < proc->max_threads &&
        (thread->looper & (BINDER_LOOPER_STATE_REGISTERED |
         BINDER_LOOPER_STATE_ENTERED)) /* the user-space code fails to */
         /*spawn a new thread if we leave this out */) {
        proc->requested_threads++;
        binder_debug(BINDER_DEBUG_THREADS,
                 "%d:%d BR_SPAWN_LOOPER\n",
                 proc->pid, thread->pid);
        if (put_user(BR_SPAWN_LOOPER, (uint32_t __user *)buffer))
            return -EFAULT;
        binder_stat_br(proc, thread, BR_SPAWN_LOOPER);
    }
    return 0;
}

static void binder_release_work(struct list_head *list)
{
    struct binder_work *w;

    while (!list_empty(list)) {
        w = list_first_entry(list, struct binder_work, entry);
        list_del_init(&w->entry);
        switch (w->type) {
        case BINDER_WORK_TRANSACTION: {
            struct binder_transaction *t;

            t = container_of(w, struct binder_transaction, work);
            if (t->buffer->target_node &&
                !(t->flags & TF_ONE_WAY)) {
                binder_send_failed_reply(t, BR_DEAD_REPLY);
            } else {
                binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                    "undelivered transaction %d\n",
                    t->debug_id);
                t->buffer->transaction = NULL;
                kfree(t);
                binder_stats_deleted(BINDER_STAT_TRANSACTION);
            }
        } break;
        case BINDER_WORK_TRANSACTION_COMPLETE: {
            binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                "undelivered TRANSACTION_COMPLETE\n");
            kfree(w);
            binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
        } break;
        case BINDER_WORK_DEAD_BINDER_AND_CLEAR:
        case BINDER_WORK_CLEAR_DEATH_NOTIFICATION: {
            struct binder_ref_death *death;

            death = container_of(w, struct binder_ref_death, work);
            binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                "undelivered death notification, %016llx\n",
                (u64)death->cookie);
            kfree(death);
            binder_stats_deleted(BINDER_STAT_DEATH);
        } break;
        default:
            pr_err("unexpected work type, %d, not freed\n",
                   w->type);
            break;
        }
    }

}

static struct binder_thread *binder_get_thread(struct binder_proc *proc)
{
    struct binder_thread *thread = NULL;
    struct rb_node *parent = NULL;
    struct rb_node **p = &proc->threads.rb_node;

    while (*p) {
        parent = *p;
        thread = rb_entry(parent, struct binder_thread, rb_node);

        if (current->pid < thread->pid)
            p = &(*p)->rb_left;
        else if (current->pid > thread->pid)
            p = &(*p)->rb_right;
        else
            break;
    }
    if (*p == NULL) {
        thread = kzalloc(sizeof(*thread), GFP_KERNEL);
        if (thread == NULL)
            return NULL;
        binder_stats_created(BINDER_STAT_THREAD);
        thread->proc = proc;
        thread->pid = current->pid;
        init_waitqueue_head(&thread->wait);
        INIT_LIST_HEAD(&thread->todo);
        rb_link_node(&thread->rb_node, parent, p);
        rb_insert_color(&thread->rb_node, &proc->threads);
        thread->looper |= BINDER_LOOPER_STATE_NEED_RETURN;
        thread->return_error = BR_OK;
        thread->return_error2 = BR_OK;
    }
    return thread;
}

static int binder_free_thread(struct binder_proc *proc,
                  struct binder_thread *thread)
{
    struct binder_transaction *t;
    struct binder_transaction *send_reply = NULL;
    int active_transactions = 0;

    rb_erase(&thread->rb_node, &proc->threads);
    t = thread->transaction_stack;
    if (t && t->to_thread == thread)
        send_reply = t;
    while (t) {
        active_transactions++;
        binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                 "release %d:%d transaction %d %s, still active\n",
                  proc->pid, thread->pid,
                 t->debug_id,
                 (t->to_thread == thread) ? "in" : "out");

        if (t->to_thread == thread) {
            t->to_proc = NULL;
            t->to_thread = NULL;
            if (t->buffer) {
                t->buffer->transaction = NULL;
                t->buffer = NULL;
            }
            t = t->to_parent;
        } else if (t->from == thread) {
            t->from = NULL;
            t = t->from_parent;
        } else
            BUG();
    }
    if (send_reply)
        binder_send_failed_reply(send_reply, BR_DEAD_REPLY);
    binder_release_work(&thread->todo);
    kfree(thread);
    binder_stats_deleted(BINDER_STAT_THREAD);
    return active_transactions;
}

static unsigned int binder_poll(struct file *filp,
                struct poll_table_struct *wait)
{
    struct binder_proc *proc = filp->private_data;
    struct binder_thread *thread = NULL;
    int wait_for_proc_work;

    binder_lock(__func__);

    thread = binder_get_thread(proc);

    wait_for_proc_work = thread->transaction_stack == NULL &&
        list_empty(&thread->todo) && thread->return_error == BR_OK;

    binder_unlock(__func__);

    if (wait_for_proc_work) {
        if (binder_has_proc_work(proc, thread))
            return POLLIN;
        poll_wait(filp, &proc->wait, wait);
        if (binder_has_proc_work(proc, thread))
            return POLLIN;
    } else {
        if (binder_has_thread_work(thread))
            return POLLIN;
        poll_wait(filp, &thread->wait, wait);
        if (binder_has_thread_work(thread))
            return POLLIN;
    }
    return 0;
}

static int binder_ioctl_write_read(struct file *filp,
                unsigned int cmd, unsigned long arg,
                struct binder_thread *thread)
{
    int ret = 0;
    struct binder_proc *proc = filp->private_data;
    unsigned int size = _IOC_SIZE(cmd);
    void __user *ubuf = (void __user *)arg;
    struct binder_write_read bwr;

    if (size != sizeof(struct binder_write_read)) {
        ret = -EINVAL;
        goto out;
    }
    if (copy_from_user(&bwr, ubuf, sizeof(bwr))) {
        ret = -EFAULT;
        goto out;
    }
    binder_debug(BINDER_DEBUG_READ_WRITE,
             "%d:%d write %lld at %016llx, read %lld at %016llx\n",
             proc->pid, thread->pid,
             (u64)bwr.write_size, (u64)bwr.write_buffer,
             (u64)bwr.read_size, (u64)bwr.read_buffer);

    if (bwr.write_size > 0) {
        ret = binder_thread_write(proc, thread,
                      bwr.write_buffer,
                      bwr.write_size,
                      &bwr.write_consumed);
        trace_binder_write_done(ret);
        if (ret < 0) {
            bwr.read_consumed = 0;
            if (copy_to_user(ubuf, &bwr, sizeof(bwr)))
                ret = -EFAULT;
            goto out;
        }
    }
    if (bwr.read_size > 0) {
        ret = binder_thread_read(proc, thread, bwr.read_buffer,
                     bwr.read_size,
                     &bwr.read_consumed,
                     filp->f_flags & O_NONBLOCK);
        trace_binder_read_done(ret);
        if (!list_empty(&proc->todo))
            wake_up_interruptible(&proc->wait);
        if (ret < 0) {
            if (copy_to_user(ubuf, &bwr, sizeof(bwr)))
                ret = -EFAULT;
            goto out;
        }
    }
    binder_debug(BINDER_DEBUG_READ_WRITE,
             "%d:%d wrote %lld of %lld, read return %lld of %lld\n",
             proc->pid, thread->pid,
             (u64)bwr.write_consumed, (u64)bwr.write_size,
             (u64)bwr.read_consumed, (u64)bwr.read_size);
    if (copy_to_user(ubuf, &bwr, sizeof(bwr))) {
        ret = -EFAULT;
        goto out;
    }
out:
    return ret;
}

static int binder_ioctl_set_ctx_mgr(struct file *filp)
{
    int ret = 0;
    struct binder_proc *proc = filp->private_data;
    struct binder_context *context = proc->context;

    kuid_t curr_euid = current_euid();

    if (context->binder_context_mgr_node) {
        pr_err("BINDER_SET_CONTEXT_MGR already set\n");
        ret = -EBUSY;
        goto out;
    }
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 0, 0)
    ret = security_binder_set_context_mgr(proc->tsk);
    if (ret < 0)
        goto out;
#endif
    if (uid_valid(context->binder_context_mgr_uid)) {
        if (!uid_eq(context->binder_context_mgr_uid, curr_euid)) {
            pr_err("BINDER_SET_CONTEXT_MGR bad uid %d != %d\n",
                   from_kuid(&init_user_ns, curr_euid),
                   from_kuid(&init_user_ns,
                     context->binder_context_mgr_uid));
            ret = -EPERM;
            goto out;
        }
    } else {
        context->binder_context_mgr_uid = curr_euid;
    }
    context->binder_context_mgr_node = binder_new_node(proc, 0, 0);
    if (!context->binder_context_mgr_node) {
        ret = -ENOMEM;
        goto out;
    }
    context->binder_context_mgr_node->local_weak_refs++;
    context->binder_context_mgr_node->local_strong_refs++;
    context->binder_context_mgr_node->has_strong_ref = 1;
    context->binder_context_mgr_node->has_weak_ref = 1;
out:
    return ret;
}

static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
    int ret;
    struct binder_proc *proc = filp->private_data;
    struct binder_thread *thread;
    unsigned int size = _IOC_SIZE(cmd);
    void __user *ubuf = (void __user *)arg;

  /*  pr_info("binder_ioctl: %d:%d %x %lx\n",
   *          proc->pid, current->pid, cmd, arg);
   */
    trace_binder_ioctl(cmd, arg);

    ret = wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);
    if (ret)
        goto err_unlocked;

    binder_lock(__func__);
    thread = binder_get_thread(proc);
    if (thread == NULL) {
        ret = -ENOMEM;
        goto err;
    }

    switch (cmd) {
    case BINDER_WRITE_READ:
        ret = binder_ioctl_write_read(filp, cmd, arg, thread);
        if (ret)
            goto err;
        break;
    case BINDER_SET_MAX_THREADS:
        if (copy_from_user(&proc->max_threads, ubuf, sizeof(proc->max_threads))) {
            ret = -EINVAL;
            goto err;
        }
        break;
    case BINDER_SET_CONTEXT_MGR:
        ret = binder_ioctl_set_ctx_mgr(filp);
        if (ret)
            goto err;
        break;
    case BINDER_THREAD_EXIT:
        binder_debug(BINDER_DEBUG_THREADS, "%d:%d exit\n",
                 proc->pid, thread->pid);
        binder_free_thread(proc, thread);
        thread = NULL;
        break;
    case BINDER_VERSION: {
        struct binder_version __user *ver = ubuf;

        if (size != sizeof(struct binder_version)) {
            ret = -EINVAL;
            goto err;
        }
        if (put_user(BINDER_CURRENT_PROTOCOL_VERSION,
                 &ver->protocol_version)) {
            ret = -EINVAL;
            goto err;
        }
        break;
    }
    default:
        ret = -EINVAL;
        goto err;
    }
    ret = 0;
err:
    if (thread)
        thread->looper &= ~BINDER_LOOPER_STATE_NEED_RETURN;
    binder_unlock(__func__);
    wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);
    if (ret && ret != -ERESTARTSYS)
        pr_info("%d:%d ioctl %x %lx returned %d\n", proc->pid, current->pid, cmd, arg, ret);
err_unlocked:
    trace_binder_ioctl_done(ret);
    return ret;
}

static void binder_vma_open(struct vm_area_struct *vma)
{
    struct binder_proc *proc = vma->vm_private_data;

    binder_debug(BINDER_DEBUG_OPEN_CLOSE,
             "%d open vm area %lx-%lx (%ld K) vma %lx pagep %lx\n",
             proc->pid, vma->vm_start, vma->vm_end,
             (vma->vm_end - vma->vm_start) / SZ_1K, vma->vm_flags,
             (unsigned long)pgprot_val(vma->vm_page_prot));
}

static void binder_vma_close(struct vm_area_struct *vma)
{
    struct binder_proc *proc = vma->vm_private_data;

    binder_debug(BINDER_DEBUG_OPEN_CLOSE,
             "%d close vm area %lx-%lx (%ld K) vma %lx pagep %lx\n",
             proc->pid, vma->vm_start, vma->vm_end,
             (vma->vm_end - vma->vm_start) / SZ_1K, vma->vm_flags,
             (unsigned long)pgprot_val(vma->vm_page_prot));
    proc->vma = NULL;
    proc->vma_vm_mm = NULL;
    binder_defer_work(proc, BINDER_DEFERRED_PUT_FILES);
}

#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 1, 0)
static vm_fault_t binder_vm_fault(struct vm_fault *vmf)
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
static int binder_vm_fault(struct vm_fault *vmf)
#else
static int binder_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
#endif
{
    return VM_FAULT_SIGBUS;
}

static const struct vm_operations_struct binder_vm_ops = {
    .open = binder_vma_open,
    .close = binder_vma_close,
    .fault = binder_vm_fault,
};

static int binder_mmap(struct file *filp, struct vm_area_struct *vma)
{
    int ret;
    struct vm_struct *area;
    struct binder_proc *proc = filp->private_data;
    const char *failure_string;
    struct binder_buffer *buffer;

    if (proc->tsk != current)
        return -EINVAL;

    if ((vma->vm_end - vma->vm_start) > SZ_4M)
        vma->vm_end = vma->vm_start + SZ_4M;

    binder_debug(BINDER_DEBUG_OPEN_CLOSE,
             "binder_mmap: %d %lx-%lx (%ld K) vma %lx pagep %lx\n",
             proc->pid, vma->vm_start, vma->vm_end,
             (vma->vm_end - vma->vm_start) / SZ_1K, vma->vm_flags,
             (unsigned long)pgprot_val(vma->vm_page_prot));

    if (vma->vm_flags & FORBIDDEN_MMAP_FLAGS) {
        ret = -EPERM;
        failure_string = "bad vm_flags";
        goto err_bad_arg;
    }
    vma->vm_flags = (vma->vm_flags | VM_DONTCOPY) & ~VM_MAYWRITE;

    mutex_lock(&binder_mmap_lock);
    if (proc->buffer) {
        ret = -EBUSY;
        failure_string = "already mapped";
        goto err_already_mapped;
    }

    area = get_vm_area(vma->vm_end - vma->vm_start, VM_IOREMAP);
    if (area == NULL) {
        ret = -ENOMEM;
        failure_string = "get_vm_area";
        goto err_get_vm_area_failed;
    }
    proc->buffer = area->addr;
    proc->user_buffer_offset = vma->vm_start - (uintptr_t)proc->buffer;
    mutex_unlock(&binder_mmap_lock);

#ifdef CONFIG_CPU_CACHE_VIPT
    if (cache_is_vipt_aliasing()) {
        while (CACHE_COLOUR((vma->vm_start ^ (uint32_t)proc->buffer))) {
            pr_info("binder_mmap: %d %lx-%lx maps %p bad alignment\n", proc->pid, vma->vm_start, vma->vm_end, proc->buffer);
            vma->vm_start += PAGE_SIZE;
        }
    }
#endif
    proc->pages = kzalloc(sizeof(proc->pages[0]) * ((vma->vm_end - vma->vm_start) / PAGE_SIZE), GFP_KERNEL);
    if (proc->pages == NULL) {
        ret = -ENOMEM;
        failure_string = "alloc page array";
        goto err_alloc_pages_failed;
    }
    proc->buffer_size = vma->vm_end - vma->vm_start;

    vma->vm_ops = &binder_vm_ops;
    vma->vm_private_data = proc;

    if (binder_update_page_range(proc, 1, proc->buffer, proc->buffer + PAGE_SIZE, vma)) {
        ret = -ENOMEM;
        failure_string = "alloc small buf";
        goto err_alloc_small_buf_failed;
    }
    buffer = proc->buffer;
    INIT_LIST_HEAD(&proc->buffers);
    list_add(&buffer->entry, &proc->buffers);
    buffer->free = 1;
    binder_insert_free_buffer(proc, buffer);
    proc->free_async_space = proc->buffer_size / 2;
    barrier();
    proc->files = get_files_struct(current);
    proc->vma = vma;
    proc->vma_vm_mm = vma->vm_mm;

    /*pr_info("binder_mmap: %d %lx-%lx maps %p\n",
         proc->pid, vma->vm_start, vma->vm_end, proc->buffer);*/
    return 0;

err_alloc_small_buf_failed:
    kfree(proc->pages);
    proc->pages = NULL;
err_alloc_pages_failed:
    mutex_lock(&binder_mmap_lock);
    vfree(proc->buffer);
    proc->buffer = NULL;
err_get_vm_area_failed:
err_already_mapped:
    mutex_unlock(&binder_mmap_lock);
err_bad_arg:
    pr_err("binder_mmap: %d %lx-%lx %s failed %d\n",
           proc->pid, vma->vm_start, vma->vm_end, failure_string, ret);
    return ret;
}

static int binder_open(struct inode *nodp, struct file *filp)
{
    int minor = iminor(nodp);
    struct hlist_node *tmp;
    struct binder_proc *proc;
    struct binder_device *binder_dev;

    binder_debug(BINDER_DEBUG_OPEN_CLOSE, "binder_open: %d:%d\n",
             current->group_leader->pid, current->pid);

    proc = kzalloc(sizeof(*proc), GFP_KERNEL);
    if (proc == NULL)
        return -ENOMEM;
    get_task_struct(current->group_leader);
    proc->tsk = current->group_leader;
    INIT_LIST_HEAD(&proc->todo);
    init_waitqueue_head(&proc->wait);
    proc->default_priority = task_nice(current);

    mutex_lock(&binder_devices_mtx);
    hlist_for_each_entry_safe(binder_dev, tmp, &binder_devices, hlist) {
        if (MINOR(binder_dev->cdev.dev) == minor)
            break;
        binder_dev = NULL;
    }
    mutex_unlock(&binder_devices_mtx);
    if (!binder_dev)
        BUG();

    filp->private_data = &binder_dev->class_dev;
    proc->context = &binder_dev->context;

    binder_lock(__func__);

    binder_stats_created(BINDER_STAT_PROC);
    hlist_add_head(&proc->proc_node, &binder_procs);
    proc->pid = current->group_leader->pid;
    INIT_LIST_HEAD(&proc->delivered_death);
    filp->private_data = proc;

    binder_unlock(__func__);

    if (binder_debugfs_dir_entry_proc) {
        char strbuf[11];

        snprintf(strbuf, sizeof(strbuf), "%u", proc->pid);
        /*
         * proc debug entries are shared between contexts, so
         * this will fail if the process tries to open the driver
         * again with a different context. The priting code will
         * anyway print all contexts that a given PID has, so this
         * is not a problem.
         */
        proc->debugfs_entry = debugfs_create_file(strbuf, S_IRUGO,
            binder_debugfs_dir_entry_proc,
            (void *)(unsigned long)proc->pid,
            &binder_proc_fops);
    }

    return 0;
}

static int binder_flush(struct file *filp, fl_owner_t id)
{
    struct binder_proc *proc = filp->private_data;

    binder_defer_work(proc, BINDER_DEFERRED_FLUSH);

    return 0;
}

static void binder_deferred_flush(struct binder_proc *proc)
{
    struct rb_node *n;
    int wake_count = 0;

    for (n = rb_first(&proc->threads); n != NULL; n = rb_next(n)) {
        struct binder_thread *thread = rb_entry(n, struct binder_thread, rb_node);

        thread->looper |= BINDER_LOOPER_STATE_NEED_RETURN;
        if (thread->looper & BINDER_LOOPER_STATE_WAITING) {
            wake_up_interruptible(&thread->wait);
            wake_count++;
        }
    }
    wake_up_interruptible_all(&proc->wait);

    binder_debug(BINDER_DEBUG_OPEN_CLOSE,
             "binder_flush: %d woke %d threads\n", proc->pid,
             wake_count);
}

static int binder_release(struct inode *nodp, struct file *filp)
{
    struct binder_proc *proc = filp->private_data;

    debugfs_remove(proc->debugfs_entry);
    binder_defer_work(proc, BINDER_DEFERRED_RELEASE);

    return 0;
}

static int binder_node_release(struct binder_node *node, int refs)
{
    struct binder_ref *ref;
    int death = 0;

    list_del_init(&node->work.entry);
    binder_release_work(&node->async_todo);

    if (hlist_empty(&node->refs)) {
        kfree(node);
        binder_stats_deleted(BINDER_STAT_NODE);

        return refs;
    }

    node->proc = NULL;
    node->local_strong_refs = 0;
    node->local_weak_refs = 0;
    hlist_add_head(&node->dead_node, &binder_dead_nodes);

    hlist_for_each_entry(ref, &node->refs, node_entry) {
        refs++;

        if (!ref->death)
            continue;

        death++;

        if (list_empty(&ref->death->work.entry)) {
            ref->death->work.type = BINDER_WORK_DEAD_BINDER;
            list_add_tail(&ref->death->work.entry,
                      &ref->proc->todo);
            wake_up_interruptible(&ref->proc->wait);
        } else
            BUG();
    }

    binder_debug(BINDER_DEBUG_DEAD_BINDER,
             "node %d now dead, refs %d, death %d\n",
             node->debug_id, refs, death);

    return refs;
}

static void binder_deferred_release(struct binder_proc *proc)
{
    struct binder_transaction *t;
    struct binder_context *context = proc->context;
    struct rb_node *n;
    int threads, nodes, incoming_refs, outgoing_refs, buffers,
        active_transactions, page_count;

    BUG_ON(proc->vma);
    BUG_ON(proc->files);

    hlist_del(&proc->proc_node);

    if (context->binder_context_mgr_node &&
        context->binder_context_mgr_node->proc == proc) {
        binder_debug(BINDER_DEBUG_DEAD_BINDER,
                 "%s: %d context_mgr_node gone\n",
                 __func__, proc->pid);
        context->binder_context_mgr_node = NULL;
    }

    threads = 0;
    active_transactions = 0;
    while ((n = rb_first(&proc->threads))) {
        struct binder_thread *thread;

        thread = rb_entry(n, struct binder_thread, rb_node);
        threads++;
        active_transactions += binder_free_thread(proc, thread);
    }

    nodes = 0;
    incoming_refs = 0;
    while ((n = rb_first(&proc->nodes))) {
        struct binder_node *node;

        node = rb_entry(n, struct binder_node, rb_node);
        nodes++;
        rb_erase(&node->rb_node, &proc->nodes);
        incoming_refs = binder_node_release(node, incoming_refs);
    }

    outgoing_refs = 0;
    while ((n = rb_first(&proc->refs_by_desc))) {
        struct binder_ref *ref;

        ref = rb_entry(n, struct binder_ref, rb_node_desc);
        outgoing_refs++;
        binder_delete_ref(ref);
    }

    binder_release_work(&proc->todo);
    binder_release_work(&proc->delivered_death);

    buffers = 0;
    while ((n = rb_first(&proc->allocated_buffers))) {
        struct binder_buffer *buffer;

        buffer = rb_entry(n, struct binder_buffer, rb_node);

        t = buffer->transaction;
        if (t) {
            t->buffer = NULL;
            buffer->transaction = NULL;
            pr_err("release proc %d, transaction %d, not freed\n",
                   proc->pid, t->debug_id);
            /*BUG();*/
        }

        binder_free_buf(proc, buffer);
        buffers++;
    }

    binder_stats_deleted(BINDER_STAT_PROC);

    page_count = 0;
    if (proc->pages) {
        int i;

        for (i = 0; i < proc->buffer_size / PAGE_SIZE; i++) {
            void *page_addr;

            if (!proc->pages[i])
                continue;

            page_addr = proc->buffer + i * PAGE_SIZE;
            binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                     "%s: %d: page %d at %p not freed\n",
                     __func__, proc->pid, i, page_addr);
            unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
            __free_page(proc->pages[i]);
            page_count++;
        }
        kfree(proc->pages);
        vfree(proc->buffer);
    }

    put_task_struct(proc->tsk);

    binder_debug(BINDER_DEBUG_OPEN_CLOSE,
             "%s: %d threads %d, nodes %d (ref %d), refs %d, active transactions %d, buffers %d, pages %d\n",
             __func__, proc->pid, threads, nodes, incoming_refs,
             outgoing_refs, active_transactions, buffers, page_count);

    kfree(proc);
}

static void binder_deferred_func(struct work_struct *work)
{
    struct binder_proc *proc;
    struct files_struct *files;

    int defer;

    do {
        binder_lock(__func__);
        mutex_lock(&binder_deferred_lock);
        if (!hlist_empty(&binder_deferred_list)) {
            proc = hlist_entry(binder_deferred_list.first,
                    struct binder_proc, deferred_work_node);
            hlist_del_init(&proc->deferred_work_node);
            defer = proc->deferred_work;
            proc->deferred_work = 0;
        } else {
            proc = NULL;
            defer = 0;
        }
        mutex_unlock(&binder_deferred_lock);

        files = NULL;
        if (defer & BINDER_DEFERRED_PUT_FILES) {
            files = proc->files;
            if (files)
                proc->files = NULL;
        }

        if (defer & BINDER_DEFERRED_FLUSH)
            binder_deferred_flush(proc);

        if (defer & BINDER_DEFERRED_RELEASE)
            binder_deferred_release(proc); /* frees proc */

        binder_unlock(__func__);
        if (files)
            put_files_struct(files);
    } while (proc);
}
static DECLARE_WORK(binder_deferred_work, binder_deferred_func);

static void
binder_defer_work(struct binder_proc *proc, enum binder_deferred_state defer)
{
    mutex_lock(&binder_deferred_lock);
    proc->deferred_work |= defer;
    if (hlist_unhashed(&proc->deferred_work_node)) {
        hlist_add_head(&proc->deferred_work_node,
                &binder_deferred_list);
        schedule_work(&binder_deferred_work);
    }
    mutex_unlock(&binder_deferred_lock);
}

static void print_binder_transaction(struct seq_file *m, const char *prefix,
                     struct binder_transaction *t)
{
    seq_printf(m,
           "%s %d: %p from %d:%d to %d:%d code %x flags %x pri %ld r%d",
           prefix, t->debug_id, t,
           t->from ? t->from->proc->pid : 0,
           t->from ? t->from->pid : 0,
           t->to_proc ? t->to_proc->pid : 0,
           t->to_thread ? t->to_thread->pid : 0,
           t->code, t->flags, t->priority, t->need_reply);
    if (t->buffer == NULL) {
        seq_puts(m, " buffer free\n");
        return;
    }
    if (t->buffer->target_node)
        seq_printf(m, " node %d",
               t->buffer->target_node->debug_id);
    seq_printf(m, " size %zd:%zd data %p\n",
           t->buffer->data_size, t->buffer->offsets_size,
           t->buffer->data);
}

static void print_binder_buffer(struct seq_file *m, const char *prefix,
                struct binder_buffer *buffer)
{
    seq_printf(m, "%s %d: %p size %zd:%zd %s\n",
           prefix, buffer->debug_id, buffer->data,
           buffer->data_size, buffer->offsets_size,
           buffer->transaction ? "active" : "delivered");
}

static void print_binder_work(struct seq_file *m, const char *prefix,
                  const char *transaction_prefix,
                  struct binder_work *w)
{
    struct binder_node *node;
    struct binder_transaction *t;

    switch (w->type) {
    case BINDER_WORK_TRANSACTION:
        t = container_of(w, struct binder_transaction, work);
        print_binder_transaction(m, transaction_prefix, t);
        break;
    case BINDER_WORK_TRANSACTION_COMPLETE:
        seq_printf(m, "%stransaction complete\n", prefix);
        break;
    case BINDER_WORK_NODE:
        node = container_of(w, struct binder_node, work);
        seq_printf(m, "%snode work %d: u%016llx c%016llx\n",
               prefix, node->debug_id,
               (u64)node->ptr, (u64)node->cookie);
        break;
    case BINDER_WORK_DEAD_BINDER:
        seq_printf(m, "%shas dead binder\n", prefix);
        break;
    case BINDER_WORK_DEAD_BINDER_AND_CLEAR:
        seq_printf(m, "%shas cleared dead binder\n", prefix);
        break;
    case BINDER_WORK_CLEAR_DEATH_NOTIFICATION:
        seq_printf(m, "%shas cleared death notification\n", prefix);
        break;
    default:
        seq_printf(m, "%sunknown work: type %d\n", prefix, w->type);
        break;
    }
}

static void print_binder_thread(struct seq_file *m,
                struct binder_thread *thread,
                int print_always)
{
    struct binder_transaction *t;
    struct binder_work *w;
    size_t start_pos = m->count;
    size_t header_pos;

    seq_printf(m, "  thread %d: l %02x\n", thread->pid, thread->looper);
    header_pos = m->count;
    t = thread->transaction_stack;
    while (t) {
        if (t->from == thread) {
            print_binder_transaction(m,
                         "    outgoing transaction", t);
            t = t->from_parent;
        } else if (t->to_thread == thread) {
            print_binder_transaction(m,
                         "    incoming transaction", t);
            t = t->to_parent;
        } else {
            print_binder_transaction(m, "    bad transaction", t);
            t = NULL;
        }
    }
    list_for_each_entry(w, &thread->todo, entry) {
        print_binder_work(m, "    ", "    pending transaction", w);
    }
    if (!print_always && m->count == header_pos)
        m->count = start_pos;
}

static void print_binder_node(struct seq_file *m, struct binder_node *node)
{
    struct binder_ref *ref;
    struct binder_work *w;
    int count;

    count = 0;
    hlist_for_each_entry(ref, &node->refs, node_entry)
        count++;

    seq_printf(m, "  node %d: u%016llx c%016llx hs %d hw %d ls %d lw %d is %d iw %d",
           node->debug_id, (u64)node->ptr, (u64)node->cookie,
           node->has_strong_ref, node->has_weak_ref,
           node->local_strong_refs, node->local_weak_refs,
           node->internal_strong_refs, count);
    if (count) {
        seq_puts(m, " proc");
        hlist_for_each_entry(ref, &node->refs, node_entry)
            seq_printf(m, " %d", ref->proc->pid);
    }
    seq_puts(m, "\n");
    list_for_each_entry(w, &node->async_todo, entry)
        print_binder_work(m, "    ",
                  "    pending async transaction", w);
}

static void print_binder_ref(struct seq_file *m, struct binder_ref *ref)
{
    seq_printf(m, "  ref %d: desc %d %snode %d s %d w %d d %p\n",
           ref->debug_id, ref->desc, ref->node->proc ? "" : "dead ",
           ref->node->debug_id, ref->strong, ref->weak, ref->death);
}

static void print_binder_proc(struct seq_file *m,
                  struct binder_proc *proc, int print_all)
{
    struct binder_work *w;
    struct rb_node *n;
    size_t start_pos = m->count;
    size_t header_pos;

    seq_printf(m, "proc %d\n", proc->pid);
    seq_printf(m, "context %s\n", proc->context->name);
    header_pos = m->count;

    for (n = rb_first(&proc->threads); n != NULL; n = rb_next(n))
        print_binder_thread(m, rb_entry(n, struct binder_thread,
                        rb_node), print_all);
    for (n = rb_first(&proc->nodes); n != NULL; n = rb_next(n)) {
        struct binder_node *node = rb_entry(n, struct binder_node,
                            rb_node);
        if (print_all || node->has_async_transaction)
            print_binder_node(m, node);
    }
    if (print_all) {
        for (n = rb_first(&proc->refs_by_desc);
             n != NULL;
             n = rb_next(n))
            print_binder_ref(m, rb_entry(n, struct binder_ref,
                             rb_node_desc));
    }
    for (n = rb_first(&proc->allocated_buffers); n != NULL; n = rb_next(n))
        print_binder_buffer(m, "  buffer",
                    rb_entry(n, struct binder_buffer, rb_node));
    list_for_each_entry(w, &proc->todo, entry)
        print_binder_work(m, "  ", "  pending transaction", w);
    list_for_each_entry(w, &proc->delivered_death, entry) {
        seq_puts(m, "  has delivered dead binder\n");
        break;
    }
    if (!print_all && m->count == header_pos)
        m->count = start_pos;
}

static const char * const binder_return_strings[] = {
    "BR_ERROR",
    "BR_OK",
    "BR_TRANSACTION",
    "BR_REPLY",
    "BR_ACQUIRE_RESULT",
    "BR_DEAD_REPLY",
    "BR_TRANSACTION_COMPLETE",
    "BR_INCREFS",
    "BR_ACQUIRE",
    "BR_RELEASE",
    "BR_DECREFS",
    "BR_ATTEMPT_ACQUIRE",
    "BR_NOOP",
    "BR_SPAWN_LOOPER",
    "BR_FINISHED",
    "BR_DEAD_BINDER",
    "BR_CLEAR_DEATH_NOTIFICATION_DONE",
    "BR_FAILED_REPLY"
};

static const char * const binder_command_strings[] = {
    "BC_TRANSACTION",
    "BC_REPLY",
    "BC_ACQUIRE_RESULT",
    "BC_FREE_BUFFER",
    "BC_INCREFS",
    "BC_ACQUIRE",
    "BC_RELEASE",
    "BC_DECREFS",
    "BC_INCREFS_DONE",
    "BC_ACQUIRE_DONE",
    "BC_ATTEMPT_ACQUIRE",
    "BC_REGISTER_LOOPER",
    "BC_ENTER_LOOPER",
    "BC_EXIT_LOOPER",
    "BC_REQUEST_DEATH_NOTIFICATION",
    "BC_CLEAR_DEATH_NOTIFICATION",
    "BC_DEAD_BINDER_DONE",
    "BC_TRANSACTION_SG",
    "BC_REPLY_SG",
};

static const char * const binder_objstat_strings[] = {
    "proc",
    "thread",
    "node",
    "ref",
    "death",
    "transaction",
    "transaction_complete"
};

static void print_binder_stats(struct seq_file *m, const char *prefix,
                   struct binder_stats *stats)
{
    int i;

    BUILD_BUG_ON(ARRAY_SIZE(stats->bc) !=
             ARRAY_SIZE(binder_command_strings));
    for (i = 0; i < ARRAY_SIZE(stats->bc); i++) {
        if (stats->bc[i])
            seq_printf(m, "%s%s: %d\n", prefix,
                   binder_command_strings[i], stats->bc[i]);
    }

    BUILD_BUG_ON(ARRAY_SIZE(stats->br) !=
             ARRAY_SIZE(binder_return_strings));
    for (i = 0; i < ARRAY_SIZE(stats->br); i++) {
        if (stats->br[i])
            seq_printf(m, "%s%s: %d\n", prefix,
                   binder_return_strings[i], stats->br[i]);
    }

    BUILD_BUG_ON(ARRAY_SIZE(stats->obj_created) !=
             ARRAY_SIZE(binder_objstat_strings));
    BUILD_BUG_ON(ARRAY_SIZE(stats->obj_created) !=
             ARRAY_SIZE(stats->obj_deleted));
    for (i = 0; i < ARRAY_SIZE(stats->obj_created); i++) {
        if (stats->obj_created[i] || stats->obj_deleted[i])
            seq_printf(m, "%s%s: active %d total %d\n", prefix,
                binder_objstat_strings[i],
                stats->obj_created[i] - stats->obj_deleted[i],
                stats->obj_created[i]);
    }
}

static void print_binder_proc_stats(struct seq_file *m,
                    struct binder_proc *proc)
{
    struct binder_work *w;
    struct rb_node *n;
    int count, strong, weak;

    seq_printf(m, "proc %d\n", proc->pid);
    seq_printf(m, "context %s\n", proc->context->name);
    count = 0;
    for (n = rb_first(&proc->threads); n != NULL; n = rb_next(n))
        count++;
    seq_printf(m, "  threads: %d\n", count);
    seq_printf(m, "  requested threads: %d+%d/%d\n"
            "  ready threads %d\n"
            "  free async space %zd\n", proc->requested_threads,
            proc->requested_threads_started, proc->max_threads,
            proc->ready_threads, proc->free_async_space);
    count = 0;
    for (n = rb_first(&proc->nodes); n != NULL; n = rb_next(n))
        count++;
    seq_printf(m, "  nodes: %d\n", count);
    count = 0;
    strong = 0;
    weak = 0;
    for (n = rb_first(&proc->refs_by_desc); n != NULL; n = rb_next(n)) {
        struct binder_ref *ref = rb_entry(n, struct binder_ref,
                          rb_node_desc);
        count++;
        strong += ref->strong;
        weak += ref->weak;
    }
    seq_printf(m, "  refs: %d s %d w %d\n", count, strong, weak);

    count = 0;
    for (n = rb_first(&proc->allocated_buffers); n != NULL; n = rb_next(n))
        count++;
    seq_printf(m, "  buffers: %d\n", count);

    count = 0;
    list_for_each_entry(w, &proc->todo, entry) {
        switch (w->type) {
        case BINDER_WORK_TRANSACTION:
            count++;
            break;
        default:
            break;
        }
    }
    seq_printf(m, "  pending transactions: %d\n", count);

    print_binder_stats(m, "  ", &proc->stats);
}


static int binder_state_show(struct seq_file *m, void *unused)
{
    struct binder_proc *proc;
    struct binder_node *node;
    int do_lock = !binder_debug_no_lock;

    if (do_lock)
        binder_lock(__func__);

    seq_puts(m, "binder state:\n");

    if (!hlist_empty(&binder_dead_nodes))
        seq_puts(m, "dead nodes:\n");
    hlist_for_each_entry(node, &binder_dead_nodes, dead_node)
        print_binder_node(m, node);

    hlist_for_each_entry(proc, &binder_procs, proc_node)
        print_binder_proc(m, proc, 1);
    if (do_lock)
        binder_unlock(__func__);
    return 0;
}

static int binder_stats_show(struct seq_file *m, void *unused)
{
    struct binder_proc *proc;
    int do_lock = !binder_debug_no_lock;

    if (do_lock)
        binder_lock(__func__);

    seq_puts(m, "binder stats:\n");

    print_binder_stats(m, "", &binder_stats);

    hlist_for_each_entry(proc, &binder_procs, proc_node)
        print_binder_proc_stats(m, proc);
    if (do_lock)
        binder_unlock(__func__);
    return 0;
}

static int binder_transactions_show(struct seq_file *m, void *unused)
{
    struct binder_proc *proc;
    int do_lock = !binder_debug_no_lock;

    if (do_lock)
        binder_lock(__func__);

    seq_puts(m, "binder transactions:\n");
    hlist_for_each_entry(proc, &binder_procs, proc_node)
        print_binder_proc(m, proc, 0);
    if (do_lock)
        binder_unlock(__func__);
    return 0;
}

static int binder_proc_show(struct seq_file *m, void *unused)
{
    struct binder_proc *itr;
    int pid = (unsigned long)m->private;
    int do_lock = !binder_debug_no_lock;

    if (do_lock)
        binder_lock(__func__);

    hlist_for_each_entry(itr, &binder_procs, proc_node) {
        if (itr->pid == pid) {
            seq_puts(m, "binder proc state:\n");
            print_binder_proc(m, itr, 1);
        }
    }
    if (do_lock)
        binder_unlock(__func__);
    return 0;
}

static void print_binder_transaction_log_entry(struct seq_file *m,
                    struct binder_transaction_log_entry *e)
{
    seq_printf(m,
           "%d: %s from %d:%d to %d:%d context %s node %d handle %d size %d:%d\n",
           e->debug_id, (e->call_type == 2) ? "reply" :
           ((e->call_type == 1) ? "async" : "call "), e->from_proc,
           e->from_thread, e->to_proc, e->to_thread, e->context_name,
           e->to_node, e->target_handle, e->data_size, e->offsets_size);
}

static int binder_transaction_log_show(struct seq_file *m, void *unused)
{
    struct binder_transaction_log *log = m->private;
    int i;

    if (log->full) {
        for (i = log->next; i < ARRAY_SIZE(log->entry); i++)
            print_binder_transaction_log_entry(m, &log->entry[i]);
    }
    for (i = 0; i < log->next; i++)
        print_binder_transaction_log_entry(m, &log->entry[i]);
    return 0;
}

static const struct file_operations binder_fops = {
    .owner = THIS_MODULE,
    .poll = binder_poll,
    .unlocked_ioctl = binder_ioctl,
    .compat_ioctl = binder_ioctl,
    .mmap = binder_mmap,
    .open = binder_open,
    .flush = binder_flush,
    .release = binder_release,
};

BINDER_DEBUG_ENTRY(state);
BINDER_DEBUG_ENTRY(stats);
BINDER_DEBUG_ENTRY(transactions);
BINDER_DEBUG_ENTRY(transaction_log);

static struct class *binder_class;

static void binder_device_release(struct device *dev)
{
}

static int __init init_binder_device(int idx)
{
    int ret;
    char *name;
    dev_t devnr;
    struct binder_device *binder_device;
    /* strlen("binder")
     * +
     * maximum length of 64 bit int as string
     */
    char numstr[6 + 21] = "binder";

    binder_device = kzalloc(sizeof(*binder_device), GFP_KERNEL);
    if (!binder_device)
        return -ENOMEM;

    cdev_init(&binder_device->cdev, &binder_fops);
    binder_device->cdev.owner = THIS_MODULE;

    devnr = MKDEV(BINDER_DKMS_MAJOR, idx);
    ret = cdev_add(&binder_device->cdev, devnr, 1);
    if (ret) {
        kfree(binder_device);
        return ret;
    }

    if (binder_devices_param > 1)
        ret = snprintf(numstr, sizeof(numstr), "binder%d", idx);
    if (ret < 0 || (size_t)ret >= sizeof(numstr)) {
        cdev_del(&binder_device->cdev);
        kfree(binder_device);
        return -EIO;
    }

    name = kzalloc(strlen(numstr) + 1, GFP_KERNEL);
    if (!name) {
        cdev_del(&binder_device->cdev);
        kfree(binder_device);
        return -ENOMEM;
    }
    strcpy(name, numstr);
    binder_device->context.name = name;
    binder_device->context.binder_context_mgr_uid = INVALID_UID;

    binder_device->class_dev.devt = binder_device->cdev.dev;
    binder_device->class_dev.class = binder_class;
    binder_device->class_dev.release = binder_device_release;
    dev_set_name(&binder_device->class_dev, "%s", name);
    ret = device_register(&binder_device->class_dev);
    if (ret) {
        cdev_del(&binder_device->cdev);
        kfree(binder_device);
        kfree(name);
        return ret;
    }

    mutex_lock(&binder_devices_mtx);
    hlist_add_head(&binder_device->hlist, &binder_devices);
    mutex_unlock(&binder_devices_mtx);

    return 0;
}

static int __init binder_init(void)
{
    int i, ret;
    struct binder_device *device;
    struct hlist_node *tmp;

    if (binder_devices_param <= 0 ||
        binder_devices_param > BINDER_DKMS_MAX_MINOR)
        return -EINVAL;

    binder_debugfs_dir_entry_root = debugfs_create_dir("binder", NULL);
    if (binder_debugfs_dir_entry_root)
        binder_debugfs_dir_entry_proc = debugfs_create_dir("proc",
                         binder_debugfs_dir_entry_root);

    if (binder_debugfs_dir_entry_root) {
        debugfs_create_file("state",
                    S_IRUGO,
                    binder_debugfs_dir_entry_root,
                    NULL,
                    &binder_state_fops);
        debugfs_create_file("stats",
                    S_IRUGO,
                    binder_debugfs_dir_entry_root,
                    NULL,
                    &binder_stats_fops);
        debugfs_create_file("transactions",
                    S_IRUGO,
                    binder_debugfs_dir_entry_root,
                    NULL,
                    &binder_transactions_fops);
        debugfs_create_file("transaction_log",
                    S_IRUGO,
                    binder_debugfs_dir_entry_root,
                    &binder_transaction_log,
                    &binder_transaction_log_fops);
        debugfs_create_file("failed_transaction_log",
                    S_IRUGO,
                    binder_debugfs_dir_entry_root,
                    &binder_transaction_log_failed,
                    &binder_transaction_log_fops);
    }

    ret = register_chrdev_region(MKDEV(BINDER_DKMS_MAJOR, 0),
                     BINDER_DKMS_MAX_MINOR, "binder");
    if (ret)
        goto on_error_remove_debugfs;

    binder_class = class_create(THIS_MODULE, "binder");
    if (IS_ERR(binder_class))
        goto on_error_unregister_chrdev_region;

    for (i = 1; i < binder_devices_param; i++) {
        ret = init_binder_device(i);
        if (ret)
            goto err_init_binder_device_failed;
    }

    return ret;

err_init_binder_device_failed:
    mutex_lock(&binder_devices_mtx);
    hlist_for_each_entry_safe(device, tmp, &binder_devices, hlist) {
        cdev_del(&device->cdev);
        device_unregister(&device->class_dev);
        kfree(device->context.name);
        hlist_del(&device->hlist);
        kfree(device);
    }
    mutex_unlock(&binder_devices_mtx);
    class_destroy(binder_class);

on_error_unregister_chrdev_region:
    unregister_chrdev_region(MKDEV(BINDER_DKMS_MAJOR, 0),
                 BINDER_DKMS_MAX_MINOR);

on_error_remove_debugfs:
    debugfs_remove_recursive(binder_debugfs_dir_entry_root);

    return -1;
}

static void __exit binder_exit(void)
{
    struct binder_device *device;
    struct hlist_node *tmp;

    mutex_lock(&binder_devices_mtx);
    hlist_for_each_entry_safe(device, tmp, &binder_devices, hlist) {
        cdev_del(&device->cdev);
        device_unregister(&device->class_dev);
        kfree(device->context.name);
        hlist_del(&device->hlist);
        kfree(device);
    }
    mutex_unlock(&binder_devices_mtx);

    class_destroy(binder_class);

    unregister_chrdev_region(MKDEV(BINDER_DKMS_MAJOR, 0),
                 BINDER_DKMS_MAX_MINOR);

    debugfs_remove_recursive(binder_debugfs_dir_entry_root);
}

module_init(binder_init);
module_exit(binder_exit);

#define CREATE_TRACE_POINTS
#include "binder_trace.h"

MODULE_LICENSE("GPL v2");
